Chapter II: Part 2

Very effective co-operation has continued to be maintained with the Office of Forest Pathology, of the U. S. Bureau of Plant Industry. Recently the salaries of all pathologists connected with the Commission have been carried by that office, and there has been constant communication and co-operation in reference to all research work.

Much excellent help has continually been given by the State Forestry Department at Harrisburg, the Deputy Commissioner, Hon. I. C. Williams, being assigned as a collaborator with this Commission.

The authorities of the University of Pennsylvania have been exceedingly courteous in granting ample space for laboratory work in the new Zoology Building. Room has also been given for laboratory work in tree medication in the Botanical Building. Franklin and Marshall College, at Lancaster, and the State College of Pennsylvania, have also provided room for laboratory work in the field investigations.

There has been a liberal interchange of ideas and helpful suggestions through correspondence with the State Conservation Commission at Albany, N. Y., the State Forester and State Pathologist of New Jersey, the State Forester of Maryland and of Massachusetts, and with officials in Virginia, West Virginia, and Maryland.

MUCH IMPORTANT WORK UNFINISHED.

The cessation of the work at this time is particularly unfortunate because so many important investigations, not yet finished, would likely have had a very practical and beneficial bearing upon the actual eradication of the disease.

First.—Very little is known about the bast miner—the insect which, as stated in another place, is probably one of the most important carriers of blight spores. A full knowledge of the life history of this insect would probably very soon have been completed, and which would be a most interesting contribution to science[7].

[7] Since writing the above, this work has already been finished, as stated in footnote on page 46.

Second.—The Chemist and Physiologist in tree medication had planned to use a new solution for injection into diseased trees, which according to chemical work already done, promises to check the growth of the blight.

Third.—The local intensive work in utilization had just begun, and as stated elsewhere, bids fair to solve largely the difficult problem of utilizing rapidly the diseased chestnut.

Fourth.—The discovery of the blight in China and the possession by the Commission of a large number of seedlings of one of the most important Chinese chestnuts, as well as immune and resistant Japanese stock, opens a field for breeding experiments which would without question have been of the greatest benefit to the owners of chestnut orchards.

Fifth.—Although not demonstrated before, it is now proved that birds and insects carry enormous quantities of spores of the blight fungus, which necessarily changes our viewpoint considerably with respect to the eradication of the disease.

Sixth.—In a number of forest tracts and several orchards, thorough “cutting-out” work and up-to-date surgery treatments have been started by expert employees of the Commission, which are just now beginning to show evidences of the value of this kind of work.

Brief statements of the results of the different lines of work conducted by the Commission follow, credited to the respective parties in charge.

FIELD OPERATIONS.

As heretofore, all field work has been conducted under the immediate direction of the General Superintendent, Mr. S. B. Detwiler. In the following statements some of the principal features of the work to date are pointed out by him, and also suggestions given to timber owners who may wish to clear their woods of blight on their own responsibility. A statement in detail of the effectiveness of sanitation cutting in controlling the blight, by Mr. Detwiler, is appended to this report.

REDUCTION OF FORCE.

A majority of the field agents of the Commission were dismissed in January, 1913, because it was believed that very little work could be done during the inclement months of winter and spring. However, the unusually open winter made it possible for the small field force retained to accomplish more for the time and money expended than at any previous time since our work was organized. An average force of 36 men in the western district and 11 men in the eastern district were in the field from the first of the year to July 25th, 1913, when all field work was discontinued.

BETTER WORK IN WINTER.

The experience of the past two years has demonstrated that more can be accomplished in locating and destroying the blight after the leaves have fallen than while the trees are in full foliage. Girdled twigs and branches bearing withered leaves are prominent at great distances in winter, and the increased amount of light admitted through the tops of the trees makes it easier to see cankers on the trunks and branches. The proper treatment of the infected trees is no more difficult in winter than in late summer or fall, unless the snow is very deep. In the badly blighted region in the eastern part of the State, field men are able to accomplish better results because most timber owners prefer to cut their timber in the winter, when they can spare the time from their farming operations.

FIELD WORK IN THE WESTERN DISTRICT.

Thorough scouting in 1912 has shown that no blight exists west of a line drawn through central Somerset and Cambria counties, along the extreme eastern border of Cameron County, to the northeast corner of Tioga County. West of this line, nine isolated spot infections were found in six counties, but all of these infections were eradicated as soon as found, and have been under careful surveillance since. These infected spots were located in Fayette, Elk, Warren, Potter, Clarion and Indiana counties, and five out of the nine spots were found to be due to the planting of diseased nursery stock purchased from nurseries in the infected region. In April, 1913, the infection in Indiana County was discovered in a shipment of three chestnut trees purchased from a nursery in New Jersey. These examples show very strikingly the ease with which the blight is widely distributed through the shipment of nursery stock. Persons who have planted nursery grown chestnut trees in regions free from the blight, should watch these trees carefully for the first appearance of the disease, and promptly destroy all infected trees.

Field work in the Western District during the period covered by this report has been confined to Tioga, Clinton, Lycoming, Centre, Huntingdon, Blair, Bedford, and Somerset counties. Tioga, Clinton, Centre, and Blair counties have been scouted and most of the diseased trees removed, but a considerable amount of infection still remains in Lycoming, Huntingdon, Bedford, and Somerset counties. In addition, Fulton and Mifflin counties still have a large amount of infection remaining, since with the small field force it was impossible to continue the work in these counties.

The accompanying map shows the progress of the control work in the Western District, and the location of infected areas. The following tabulation is a statement of the number of infected trees found and cut out in the Western District from the time the work was begun until July 1st, 1913:

Map showing spot infection in the western half of Pennsylvania to July 1, 1913, indicated by circles. Figures inside the circles indicate the number of diseased trees found in each locality.

Inspection in eastern half of the State is generalized from the best information available.]

STATEMENT OF CHESTNUT BLIGHT INFECTION IN THE
WESTERN DISTRICT.

==============+==================+==============+==============
County. | Number of tracts | Total number | Total number
| on which | of infected | of infected
| infection was | trees found. | trees removed.
| found. | |
--------------+------------------+--------------+--------------
Allegheny, | | |
Armstrong, | | |
Bedford, | 147 | 4,027 | 2,787
Bradford, | 91 | 1,048 | 829
Blair, | 225 | 1,884 | 1,680
Beaver, | | |
Butler, | | |
Cameron, | | |
Centre, | 142 | 2,556 | 1,763
Clinton, | 169 | 3,481 | 2,704
Clearfield, | 9 | 117 | 117
Clarion, | 1 | 1 | 1
Cambria, | 9 | 450 | 450
Crawford, | | |
Elk, | 6 | 377 | 377
Erie, | | |
Fayette, | 2 | 11 | 11
Fulton, | 90 | 1,902 | 900
Forest, | | |
Greene, | | |
Huntingdon, | 233 | 5,287 | 4,771
Indiana, | 1 | 1 | 1
Jefferson, | | |
Lycoming, | 259 | 5,015 | 4,486
Lawrence, | | |
Mifflin, | 95 | 1,976 | 1,468
McKean, | | |
Mercer, | | |
Potter, | 1 | 1 | 1
Somerset, | 92 | 9,110 | 8,093
Sullivan, | 22 | 207 | 207
Tioga, | 12 | 43 | 43
Venango, | | |
Westmoreland, | | |
Washington, | | |
Warren, | 3 | 16 | 16
+------------------+--------------+--------------
Total, | 1,609 | 37,510 | 30,705
--------------+------------------+--------------+--------------

A HARMLESS SAPROPHYTE.

Persons familiar with the appearance of the chestnut blight fungus may easily confuse it with another fungus found in Washington, Greene, and Fayette counties. This fungus (_Endothia radicalis_ Schw.), (Denot.) is related to the blight fungus (_Endothia parasitica_ Murr.) (And.), but is found only on dead wood and bark and does not attack living tissues. It has been thoroughly studied by the field pathologist, since at first it was feared that it might have parasitic tendencies. Continued investigation proves beyond doubt that this fungus is a harmless saprophyte which need not be feared. It need not be confused with the parasitic species by those who have the opportunity to compare them.

FIELD WORK IN THE EASTERN DISTRICT.

Field work in the Eastern District has been conducted mainly on the plan outlined in the previous report. Inspections were made on the request of timber owners and advice given as to the best method of procedure in each case. Particular attention was given to assisting owners of blighted chestnut in finding the best markets for the products. On the request of owners desiring to take advantage of the reduced freight rates on blighted chestnut cordwood, inspections were made and necessary certificates issued. Supervision of enforced cutting of all blighted chestnut trees within a half mile of chestnut orchards in which the owners are endeavoring to keep the disease under control, was continued.

As the evidences of the blight become more noticeable and the seriousness of the situation forces attention, owners of chestnut timber in eastern Pennsylvania have shown an increasing interest in the work of controlling the blight, and more requests for assistance were received than could be given individual attention. For the guidance of owners who wished to clean their woods of blight, either by doing the work themselves or having it done by contract, the following suggestions were made by the Office of Utilization. These suggestions are for use in eastern Pennsylvania only, where the blight is general.

SUGGESTIONS FOR TIMBER OWNERS.

1. It is always advisable in cutting blighted chestnut to clean up the ground thoroughly and burn all infected material, for the sake of the future crop and the community as a whole. Even if financial reasons make it impossible to treat the stumps properly, the brush and refuse should be burned, and all merchantable material removed from the tract within a reasonable period. Where the percentage of blight is very high, it is advisable to cut all the chestnut trees rather than attempt to remove only the diseased trees.

2. Stumps should not be cut higher than the diameter of the tree, but this may be impracticable in sprout growth timber. A low stump saves the best end of the log, and causes the succeeding generation of sprouts to be firmly rooted.

3. Where practicable, all timber should be peeled. Poles, ties, posts and rails, should be skidded to one or more convenient places. The bark and chips collected at these points should be burned, since this refuse is very frequently the breeding place of the blight fungus.

4. It is advisable to remove all bark from the stumps down to the mineral soil, to prevent the further spread of the disease by its growth on this bark. Unpeeled stumps, even if free from blight at the time the tree is felled, are very apt to become infected, and the disease will then eventually destroy the sprouts at the base. Stumps of trees cut in winter while the bark is “tight” may be left until spring, and peeled when the sap is ascending. Stumps made in summer should be peeled at once.

5. All chestnut refuse, including the brush from the tops, bark from stumps, chips, etc., should be collected and burned at as early a time as may be done with safety from fire. Green tops of trees felled in summer can be burned immediately by close piling over a well-started fire. The danger of infecting the sprouts from the stump is lessened if the fire be made over the stump after peeling. Stumps can be more cheaply sterilized, however, by painting them with creosote, and creosote also appears to be absolutely effective in keeping the stump free from infection, whereas a fire seldom chars the base of the stump sufficiently.

6. Woodsmen, while cutting and removing chestnut, should do as little injury as possible to the remaining trees, whether large or small. When the work is done by contract, trees carelessly broken in felling chestnut should be paid for at their market value. Merchantable chestnut left in the woods, either cut or uncut, when contracts call for the removal of all of the same, should be paid for at its market value.

7. Great care should be exercised in burning material so as not to injure other trees, or allow fires to remain unwatched in the woods. Forest fires may result, causing much damage. Burning should not be done when the woods are very dry, or a high wind is blowing.

LOCAL INTENSIVE FIELD WORK.

Early in the spring a more extensive plan of field work in the southeastern portion of the State was adopted. A locality was selected where the blight is beyond control, and immediate utilization necessary to avoid serious financial loss. The boundaries of the area selected were so made that the timber in all of the woodlots in the area could be handled in much the same way as though the woodlots comprised a single tract. A map showing the exact location of all of the woodlots was made, and a field agent detailed to estimate merchantable chestnut in the form of saw logs, poles, ties, posts and cordwood in each woodlot. The local market for these products was then ascertained, to determine whether all timber on the area could be best sold locally on in outside markets. At the same time the field agent interested the owners of the woodlots in the prompt removal and utilization of their chestnut trees before greater loss was occasioned by the blight. Usually the owner of a considerable quantity of blighted trees is anxious to follow this course, but the scarcity of competent woodsmen makes it difficult or impossible. In such cases, the Office of Utilization presented the data obtained by the field agent to operators of portable saw mills, stave mills, pole or tie cutters, as the facts warranted, and as many buyers as possible were interested in locating on the area. So far as there was time to test this plan, it appears that this is the cheapest and most effective way of getting results in the eastern district, since what is desired is to get cutting started on a sane and profitable basis, and this a mere general method of work usually fails to accomplish. Success or failure depends on whether or not buyer and seller can be brought together on a satisfactory basis. The work must be profitable to both owner and dealer. A competent and well-informed field agent can work out a comprehensive plan for disposing of all the merchantable chestnut in a community. Through his knowledge of prices, rates, specifications, sanitation measures, etc., he is the means of saving timber owners from much of the loss occasioned by the blight.

DISEASE INVESTIGATIONS AND NURSERY INSPECTION.

As before reported, the investigation of the blight fungus and the nursery inspection work are under the direction of Dr. F. D. Heald. Mr. P. J. Anderson has given special attention to certain field investigations, including the work at Charter Oak. Statements of some of the principal features of the work here follow:

GERMINATION OF SPORES.

Pycnospores of the blight fungus, sometimes called summer spores, germinate much more slowly than the ascospores, or so-called winter spores. The type of growth and size of colonies are different in the early stages of development on culture media.

PRODUCTION OF PYCNOSPORES IN WINTER.

In the case of this fungus the term “summer spores” is very misleading, as these spores are produced at all times of the year, being washed down in large numbers from blight cankers following each winter rain.

BIRDS DISSEMINATE THE FUNGUS.

Careful experiments show that birds act as carriers of spores of the blight fungus. Thirty-six birds belonging to nine different species have been tested. Nineteen were found to carry pycnospores, the maximum number obtained from a single bird, (Downy woodpecker), being 757,074. The highest number was always obtained from birds shot a few days after a rain period.

“SHOOTING” OF ASCOSPORES.

The ascospores are expelled forcibly, but this expulsion depends upon temperature as well as moisture. No expulsion took place in the field from November 26th, 1912, to March 21st, 1913, the temperature during the winter rains being too low. Bark containing ascospore pustules has continued to expel ascospores for over six months, (in the laboratory).

EFFECT OF TEMPERATURE.

Pycnospores are easily killed by heat, (51°C). Ascospores are slightly more resistant, only a few being able to survive 57°C.

RESISTANCE OF PYCNOSPORES.

Pycnospores are easily killed under certain conditions, but can survive in considerable numbers under certain other circumstances. Their length of life in water depends to some extent upon the temperature. Thirty-three per cent. survived in water at 55°C, after 42 days. A large percentage can survive freezing for a considerable period. They are washed down to the ground from blight cankers, during every rain, and have never been found to disappear entirely from the soil during the longest periods between rains. As many as 12 per cent. of those originally present in a soil sample have survived drying for 63 days. The longevity of the pycnospores is greater in the “spore horn” stage than when they are separated by rains and then dried. They have been killed in twenty-four hours by drying in certain tests, while the act of drying alone is generally responsible for the death of 50-60 per cent.

EFFECT OF DRYING ON ASCOSPORES.

Ascospores when shot on to glass slides have been reported as being very resistant to drying. In nature they are generally separated and washed by the rains. Laboratory tests under such conditions indicate that they are very sensitive to desiccation. Drying alone has been found to kill as many as 94 per cent. in certain tests.

ENTRANCE OF BLIGHT IN GALLS.

A small gall on the chestnut due to a lepidopterous insect (moth) has been found to be one of the places of entrance of the blight fungus. Twenty-eight per cent. of those tested showed young blight infections.

INSECTS AS CARRIERS OF THE DISEASE.

Insects may act as carriers of the spores of the blight fungus. Of a total of 75 tested, many were found to be carrying spores. The maximum number of spores of the blight fungus (336,900), was obtained from a small beetle, (_Leptostylus maculata_), which has been mentioned as a possible beneficial agent on account of its pustule-eating habits.

OTHER DISEASES OF THE CHESTNUT.

There is another “canker disease” of the chestnut prevalent in the State which is entirely distinct from the blight. It is even more important as a disease of oaks than chestnut, and is known to occur on chestnut oak, red oak, and white oak. A _dieback_ of the chestnut is not uncommon. Still another fungus appears to be associated with this trouble. A _tip blight_ of the chestnut has also been found, and in connection with it, a third species of fungus.

FIELD INVESTIGATIONS.

A field laboratory has all along been maintained at Charter Oak, and much of the outdoor inoculation work and other experiments have been conducted in that vicinity. Experiments have been conducted here on the rate of growth of blight cankers, details of which are tabulated in another manuscript, submitted for a bulletin. It is sufficient to say here that the retarding influence of the winter season is shown by these experiments. On the other hand, the cankers have continued to spread even in the winter, though the growth is much more rapid in the summer months.

Inoculations have been made both with ascospores and with pycnospores during every month of the last year. No cankers have appeared as yet from winter inoculations.

Other species of trees besides chestnut have been inoculated with the blight fungus in larger numbers than last year, special attention being given to the oaks. As yet there is no evidence that the blight fungus will establish parasitic relation with any other host, although occasionally a canker will be produced.

Careful tree surgery experiments have been conducted at Charter Oak, and to date only three cases are reported in which the canker continued to spread after cutting out and treatment.

NURSERY INSPECTION.

The office records give the following information in regard to each nursery inspection:—date, name and location of nursery, number of trees inspected, number of trees rejected, fungicides used for dipping the stock, name and location of purchaser of stock.

The nurseries from which chestnut stock was shipped during the fall of 1912 and spring of 1913, are as follows:—C. K. Sober, Paxinos, Pa.; Hoopes Bros. & Thomas, West Chester, Pa.; Lovett Nursery, Emilie, Pa.; Rakestraw & Pyle, Kennett Square, Pa.; Morris Nursery, West Chester, Pa.; Cheltenham Nursery, Oak Lane, Pa.; Jos. Moore, Montoursville, Pa.; S. L. Cummings & Co., Dewart, Pa.; and Marietta Nursery, Marietta, Pa.

In the fall of 1912, 6,538 trees were inspected. Of these 81 were rejected, and the remainder 6,457, distributed. In the spring of this year 5,305 trees were inspected, of which 195 were rejected and the remainder 5,110 distributed. The trees rejected were either infected with chestnut blight, or showed doubtful incipient infections. In case of doubt the inspectors were instructed to reject the tree. The number of rejected trees, however, is no indication of the percentage of blight in any nursery, since many diseased trees are removed from the nurseries previous to the time of making shipments, and only those thought to be healthy trees are offered for inspection.

Probably the greater portion of the trees went to purchasers in either Pennsylvania or New York. In case of re-distribution by other dealers, however, the final destination of the stock is not known. According to available records, the trees were sold to purchasers in the following States.—California, Colorado, Connecticut, District of Columbia, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Michigan, Missouri, Nebraska, New Hampshire, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, and Wisconsin.

INSECT INVESTIGATIONS.

The investigations to determine what part, if any, insects take in the transmission of the chestnut blight have been continued under the immediate direction of Prof. A. G. Ruggles. A number of interesting facts have been determined, but several important studies were just well under way when the work was suspended.

The relation of insects to blight dissemination comes under three headings; first, insects that carry the spores of the fungus and actually start new infections at the time; second, insects that carry the spores but do not directly start infections; and third, insects that make wounds in which infection readily takes place through spores carried by some other agency.

INSECTS CAUSING DIRECT INFECTION.

To the present time very little definite data have been obtained on this point, but the longer the subject is studied, the more probable it appears that ordinary insects traveling over a tree, although they may carry hundreds of spores on their bodies, do not directly start new infections.

INSECTS CARRYING SPORES BUT CAUSING NO DIRECT INFECTION.

Ants were allowed to run over cankers showing pycnidial pustules or “spore horns,” and also cankers where ascospores were shooting, and then placed in flasks of sterile water and washed from two to twenty-four hours. Plate cultures made from this material showed in many instances the presence of blight spores on the bodies of the ants. In the same way it was determined that other insects to the number of about twenty species also carry the spores of chestnut blight. The number of spores carried in each instance varied from a very few to the enormous number of 336,900. The particular insect, (_Leptostylus maculata_), carrying the 336,900 spores mentioned, is one of the beetles named in a recent press notice of the U. S. Department of Agriculture, as being very active in eating spores of the blight fungus. Therefore this beetle while destroying spores of the blight is at the same time covering its body with thousands of other chestnut blight spores which it carries from tree to tree, making it probably an injurious insect, instead of a beneficial one in this respect.

INSECTS MAKING WOUNDS IN TREES THUS OPENING THE WAY FOR INFECTION.

This is probably the most serious way in which insects are related to blight dissemination. Among the most serious of wound making insects are the seventeen-year cicadas, tree-hoppers, bark borers, and bast miners. Of these only two have been studied closely,—the cicadas and the bast miners.

CICADA STINGS.

In 1911 there was a brood of seventeen-year cicadas in several counties in the eastern part of Pennsylvania. The relations that these stings bore to blight infection have been studied near Lehighton. Many counts were made on trees and sprouts. While only 4.3 per cent. to 10.4 per cent. of all stings were found to be infected with chestnut blight, from 86 per cent. to 93.8 per cent. of all infections were in stings. This cicada injury was studied where the blight seemed most abundant. In the same tract where blight was less prevalent, other counts were made with less striking results. These observations would seem to show that blight infection is influenced considerably by the number of wounds made, but that infection many times does not take place through a wound although seemingly appropriate openings for catching blight may be present.

THE BAST MINER.

The work of the bast miner was first called to our attention by Mr. S. B. Detwiler. It is believed to be the most important insect causing wounds in the chestnut. Experiments and studies up to the present time make it probable that the bast miner is responsible for much blight infection. To understand thoroughly the relationship of this insect to the blight fungus, the life history has to be known. Much time has been spent upon this subject, but unfortunately to date, the work has not been completed.[8] The injurious period of its life history has been obtained, but the period that would have to do with its suppression, namely the adult period and time of egg laying, has not been discovered.

LARVAL EXIT HOLES AS POINTS OF INFECTION.

Hundreds of sticks of smooth bark trees of chestnut were examined during the past winter and spring to determine the number and nature of the larval exit holes of the bast miner. Every piece a foot long and over two inches in diameter had bast miner burrows present. The lowest number for a linear foot was one burrow while the highest was fifteen. The number of exit holes for a small tree, therefore, would vary from ten to one hundred and fifty. In one acre of chestnut trees the number of these exit holes would be enormous. In the light of what we now know, recent observations show that 50 per cent. of this class of infections originated in bast miner exit holes.[8]

[8] Since writing the above, Prof. Ruggles has produced the mature insect in breeding experiments and has thus completed our knowledge of its life history, and finds the insect to be a species new to science.

CROTCH INFECTIONS.

Many infections are known to start around crotches, and we speak of them as crotch infections. The eggs of the bast miner are laid near crotches and the newly hatched larvas may make entrance holes sufficiently large to allow spores of blight to enter. Here again the bast miner may be responsible, and if such proves to be a fact, this insect would be the indirect cause of 90 per cent. instead of 50 per cent. of the infection on smooth bark trees. All other insects mentioned as making wounds, with perhaps the exception of the tree hoppers, are local or else the number of wounds is not appreciable; but in the case of the bast miner, the insect is found wherever the chestnut grows.

EXPERIMENTS WITH ANTS.

Ants being found so commonly around blight cankers on chestnut trees, it has been claimed that in some instances they are responsible for as much as 90 per cent. of blight dissemination. To obtain information on this matter, it was decided during the winter to experiment with ants in the greenhouse. Two rooms were set off as an insectary. The inner of these two rooms being thoroughly sterilized, was called the sterile room, and the outer room was called the blighted room. In the latter as much blight material of the kind required as could be obtained was kept and placed on the ant table, where three colonies of ants made their homes. From the table in this room the ants were allowed to run through a glass tube to sterile seedling trees in the sterile room. The ants were of the same species as those suspected of carrying the blight, and were the common mound-builders, (_Formica integra_), being obtained in the region of Lewisburg, Union County.

The result of the experiment was that with the exception of a few dried leaves on each tree which were chewed or worked on by the ants, the trees in the sterile room are as healthy as when first placed on the table to be run over by the ants. The indication, therefore, is that ants are not responsible for blight infection.

INFECTION IN GALLS.

A more or less cylindrical gall is found on the tips of branches and on sprouts of chestnut, caused by an insect claimed to be a moth. At West Chester and Valley Forge, these galls are very numerous. Out of 161 galls examined by the plant pathologist, forty-five of the 28 per cent. showed the presence of blight, while 49 per cent. showed the presence of another fungus. A gall that shows the presence of chestnut blight in such a large percentage of cases should be given careful study.

CHEMICAL INVESTIGATIONS.

EXCESS OF TANNIN IN DISEASED WOOD.

The principal features of the chemical investigations which have been continued in charge of Mr. Joseph Shrawder, are as follows:

The abnormal tannin content of infected material was the chief subject of interest in the last report. Invariably, infected wood and hypertrophied material continue to show a higher tannin content than sound material from the same sample.

LOSS OF VOLATILE MATTER.

Moisture and other volatile matter proved of interest also. By prolonged heating at temperatures up to 155°C, infected material showed a greater ratio of loss.

CELLULOSE DETERMINATIONS.

A series of cellulose determinations was also made to note the effect of the fungus on wood and bark. A higher percentage of cellulose in sound material leads us to believe that it is being digested with the formation of acids and other soluble matter. It may also be that part of this soluble matter is reported as tannin by the hide powder method. This, with the deficiency of cellulose, may account for the relative high tannin content appearing on analysis.

CHEMICAL CHANGES.

The determination of starch, reducing sugar, and nitrogen shows that decided chemical changes are being produced by the fungus. However, this work was not brought to a satisfactory conclusion owing to the sudden termination of the work of the Commission.

NEW INJECTION MATERIAL FOR TREE MEDICATION.

Some preliminary work was also started in a search for a suitable injection material to be used in the tree medication experiments. It is evident from the chemical investigation that a suitable injection material must not coagulate the excessive tannin and other colloids in the wood and bark, and that it must be able to penetrate cutin in suberin in order to diffuse properly through the infected area. A brief investigation of a modified chlorine solution showed that it fulfilled these requirements in many respects, but its value in treating trees has not been determined.

TREE MEDICATION.

The experiments in tree medication, in charge of Dr. Caroline Rumbold, have been for some time conducted in a large chestnut orchard located near Martic Forge, Lancaster County. The following is a brief statement of recent work:

PLOTS UNDER EXPERIMENT.

In 1912 three plots were selected for experiment. Each contained about fifty trees varying in age from seedlings to eighteen years old. This year two new plots were added to the three of 1912. Some tree surgery work was done, and the trees sprayed with lime-sulphur.

OBSERVATIONS OF THE WORK OF 1912.

Last year fifty-four trees were injected; 15 with salts of the heavier metals; 5 with formaldehyde; 12 with stains; 22 with alkalies, and the remainder with water. An attempt was made to inject two trees with canker extract, but the solution would not go into the trees.

On June 7, 1913, results of observations on these trees injected last year were made as follows:

To date, the injections of the salts of the heavier metals, (copper, zinc, barium), appear not to have killed the trees, although they mutilated them. Those injected with the copper salts suffered the most. Inoculations made on these trees after they were injected have taken, and the cankers forming are larger than those on the check trees. Of the five trees injected with the formaldehyde, two are alive, but mutilated. Inoculations on these trees have formed cankers larger than those on the check trees. Most of the trees injected with stains have been cut down, for observation. None were killed, however, by the injection. The trees injected with water are in good condition with the exception of one tree infected with a canker, which is now girdled. The only unusual sign about the tree is the large amount of suckers at its base.

FAVORABLE EFFECTS OF ALKALIES.

The trees injected with alkalies are all in good condition at present. An encouraging feature of the experiment with alkalies is that a number of inoculations on these trees did not take, and on those which have taken cankers have formed smaller than those on the check trees. These trees were cut into in April in order to count the number of inoculations that took, and in a number of cases these cuts have formed callus.

INJECTIONS IN 1913.

The past spring, 69 trees have been treated—21 with colloids, 18 with alkalies, 18 with acids, 17 with benzenes, one with methyl alcohol, and two with methylene blue, while five are water checks. The method of injection used this year is the same as in 1912.

EFFECTS OF THIS YEAR’S INJECTIONS.

The trees have not reacted to the injections this year as quickly as last summer. The slowness of reaction may be due to the season of the year, the cool weather, and the large amount of rain since injections began. As was to be expected, the trees have reacted to the injections differently. Potassium chromate and bi-chromate caused the fastest and most severe reactions. Reactions of the trees to the chemicals are generally shown by discoloring, drying, or falling leaves. Sometimes the trunk shows the path the solution followed by sunken areas, or long cracks in the bark, extending up the tree. So far no results can be given as to the effect of this year’s injections, either on the trees themselves or on the canker growth. The full effect of the present injections probably cannot be seen until next year.

TREE SURGERY.

INDIVIDUAL TREE EXAMINATIONS.

The tree surgery work was continued in charge of Mr. Roy G. Pierce. A brief statement of the work here follows:—

Numerous requests for examinations of individual trees have been received continuously up to the time of closing our work. These requests have come from owners of individual lawn trees, owners of cultivated orchard trees, and owners of wood lots or small forest properties. When desired the owners or the gardeners were instructed how to take care of the trees. This is the most satisfactory way of handling this kind of work, since frequent examinations during the growing season are necessary to keep the chestnut blight under control. The owner, if well informed, may notice a diseased twig or branch at any time and remove it before the infection has spread any further. On request, the names of reputable tree surgeons have been given the owners.

ADVICE IN FOREST MANAGEMENT.

Frequently where there have been a large number of infected chestnut trees in the forest, as on Mount Penn and on the Neversink Mountain at Reading, or at Galen Hall, Wernersville, Berks County, the owners have not been so desirous of prolonging the life of the chestnut trees as of maintaining a grove or woodlot of trees of different kinds. In such cases the first principles of forestry have been recommended, namely, requiring the removal of trees that were becoming badly diseased, thus giving place to other tree species coming up beneath, such as hickories and oaks, instead of advising any tree surgery.

Tree surgery. Operator has gouged outer rim of canker, leaving mycelium of chestnut blight in center. Other cuts shown on tree were made at an earlier period.]

CONTACT WITH THE PEOPLE.

In thus meeting the people themselves, it has been possible to inform them much more thoroughly on the real cause of the blight than can be done through the medium of bulletins or newspaper articles. Many still think that the chestnut blight is caused by an insect or a mysterious something that kills the trees by descending on them as a vapor. To these people, however, “seeing is believing.”

EXPERIMENTS.

Experiments have been started at different points:—(1) On methods of cutting out cankers; (2) With substances used as sterilizing agents and as water-proofing; (3) On the charring of cankers for various periods of one to five minutes; and (4) On the uses of various fungicides and water-proofings for painting over the cankers.

EXPERIMENTS WITH LIME-SULPHUR.

The use of the lime-sulphur spray to prevent infection has been experimentally tried at several places on orchard chestnut trees. One of the most important of these experiments is one that was started in Chester County in an orchard of 200 chestnut trees, 41 trees being used for the experiment, the trees ranging in height from 15 to 35 feet, and about twenty-five years of age. At the time of closing the work of the Commission, these experiments have not yet been continued for one year, therefore no definite results have been obtained, nor can any definite conclusion be drawn.

ALLEGED CURES FOR THE BLIGHT.

Besides the trials of different treatments at Emilie, Bucks county, mentioned elsewhere, three residents of Pennsylvania, who claim they have cures for the chestnut blight, have been permitted to demonstrate the efficacy of their cures at other points. Two of these “cures” are already failing at the present time.

LOCATION OF CANKERS.

An observation which may be of importance is that blight cankers are very seldom found to have started on the underside of branches.

VALUE OF TREE SURGERY WORK.

The work of tree surgery thus far has shown that it is possible to save chestnut trees that are diseased with the chestnut blight. This can only be done, however, by the most careful tree surgery, followed by frequent examinations for new infections and the spread of the old ones. Young, smooth bark trees are more easily saved than old thick bark trees, because it is much easier to discover the blight on the former than on the latter.

OTHER TREE SURGERY WORK.

In addition to the tree surgery work under the immediate direction of Mr. Pierce, other competent employees of the Commission have done similar work at Emilie, Charter Oak, and in a large orchard at Paxinos, the results of which up to this date are considered as largely successful.

The accompanying figures, No. I and No. II, will illustrate certain phases of the tree surgery work.

GEOGRAPHIC WORK.

WEATHER CONDITIONS.

A brief statement of some additional work by the Geographer, Dr. F. P. Gulliver, follows:—

Since the last report very few definite facts have been obtained as to the relation of rainfall to the spread of the blight, but nothing has yet been learned which would contradict the opinion previously stated that blight dissemination increases much more rapidly during rainy periods.

RELATION OF SOILS TO BLIGHT OCCURRENCE.

Considerable time has been given recently to a study of the character of the soils in different localities in the State where there is more or less chestnut blight, to determine whether there is any real relation between the nature of the soil, and the amount of the disease in any locality.

LOCATION OF OBSERVATIONS.

After a careful survey of the State, it was decided to conduct this study in—(1), Chester Valley; (2), The Kutztown Valley, Berks County, and (3), Center County. To date, there has been time only to make observations in the first two localities. In the Chester Valley these studies have been much facilitated because of the constant occurrence of limestone toward the base of the mountains, and of shales toward the top. Usually, more chestnut blight was found near the tops of the mountains, and less, as one descends towards the valley.

RESULTS OF OBSERVATIONS.

The results of these observations on the relation of limestone or other alkaline soils to blight distribution, are as follows, which are simply, however, what appear to be the facts obtained from studies to date, and are not put forth as absolute conclusions.

(1)—In every series of tracts taken from limestone to overlying shale soils, the percentage of blight is least at a comparatively short distance (50 to 200 ft.), from the edge of the limestone.

(2)—Tracts on soils derived from limestone which show the highest percentage of blight seem to be those where the soil has become acid from underground drainage, and consequent leaching out of the alkalies.

(3)—Chestnut trees on soils derived from other alkaline rocks show less blight than is found in the trees on shale soils with limestone underneath.

(4)—Where the rocks have been faulted, and an older crystalline rock has been brought up to the level of the later formed limestone, there does not appear to be any less blight on the crystalline rock near the limestone.

RELATION OF ALTITUDE TO BLIGHT DISTRIBUTION.

On about 200 tracts examined, there does not seem to be any relation between the percentage of blight and the elevation above sea level.

UTILIZATION.

At the time of the last report, the work of “Utilization” was in charge of Professor J. P. Wentling. He continued to direct this work until March 1, 1913, when his leave of absence expired, and he resigned to resume his duties in the Forest School of the University of Minnesota. From that date, Mr. W. M. Kirby acted in charge of the office work, while Mr. J. R. Wilson was made directly responsible for the field operations. Until a suitable specialist could be obtained, the General Superintendent, Mr. S. B. Detwiler, has had general direction temporarily, of all the utilization work.

PRELIMINARY WORK.

For sometime, naturally, a great deal of information had to be obtained as to timber owners, purchasers of chestnut products, portable saw mills, demands for various kinds of products, etc., besides working out a general plan of active procedure. This had been largely done by Professor Wentling, before leaving, and he had already pointed out the importance of the portable mill operator, the necessity of experiments in deterioration of blighted chestnut, and of making tests of certain chestnut products through reputable manufacturers, and also the desirability of a trial of intensive local utilization in a few localities, and showed that it was desirable to keep in close touch with the important lumber associations.

CONCLUSIONS OF UTILIZATION CONFERENCE AT TRENTON.

At a Utilization Conference between various State and National officials held at Trenton, New Jersey, certain conclusions were arrived at as to special lines of work in utilization. Among these, it was recommended that the individual States take up local market studies.

LOCAL INTENSIVE UTILIZATION.

In accordance with the conclusions of the Utilization Conference above mentioned, and in line with the suggestion of the Forester of this Commission previously in charge of Utilization, it was decided to try such local work at one or two points in this State, the work being under direction of the General Superintendent. The first place selected was in the vicinity of West Chester, Chester county. The local market for various chestnut products was thoroughly exploited to determine what amount could be taken care of in local consumption, and afterwards it was determined so far as possible, how much of the surplus could be disposed of at more distant markets. The results of the work have been very interesting, and bid fair to solve largely the entire problem of utilization.

RESULTS OF THE LOCAL WORK.

In the short time that has been given to this work, up to the date of closing, remarkable progress has been made, as the following statement shows:—

(1)—Careful estimates of timber were made of 14 tracts, in the vicinity, ranging in size from 2 to 26 acres each.

(2)—Various satisfactory interviews were obtained with the timber owners, and in this connection, it was found that there has been much change in the sentiment of owners, favorable to a rapid disposal of blighted chestnut.

(3)—All local timber operators were interviewed.

(4)—It was found that the owners themselves could use a large amount of their own timber for fencing.

(5)—Lists of buyers of chestnut products were obtained at West Chester, Downingtown and vicinity, and along the Pennsylvania Railroad main line.

(6)—After getting the confidence of timber owners, they were quite willing to place the disposal of their chestnut wholly in the hands of Commission employees.

(7)—One thousand ties were sold to a street railway company, and orders were expected for 5,000 more.

(8)—Arrangements were made for installing a saw mill in the area.

(9)—At the time of closing the work, efforts were being made to obtain 20,000 poles for a firm in New Jersey.

DIFFICULTY OF OBTAINING LABOR.

In the particular local work above referred to, the difficulty of obtaining labor was encountered, as in all other cases of work of this kind. Here again, however, the Commission employees were able to aid timber owners and operators greatly by obtaining hands from a distance, until finally eight different timber owners were on the waiting list to use wood-cutters who had been imported through our efforts.

WORK IN OTHER LOCALITIES.

No doubt results similar to those mentioned above could be obtained in the same way in other localities. Such work was successful in Lebanon County, to the extent of being able to locate ten different portable saw mills in active work in that county inside of one month.

DETERIORATION EXPERIMENTS.

An experiment, probably the first of its kind, has been installed by this Commission in co-operation with the United States Forest Service, at Mt. Gretna, Lebanon County, Pennsylvania, to determine accurately the effect of the chestnut blight on the quality of chestnut wood products, and upon the durability of such products. Chestnut telephone poles, some diseased and some from healthy wood, have been set. Thirty standard railroad ties, partly diseased, and partly not, were placed in a siding of the Cornwall & Lebanon Railroad. A fence was made with mortised posts and rails, some of them from diseased trees, and others from healthy trees. To determine the direct effect of blight lesions in telephone poles, cross arms were placed through these lesions; also some fence posts were set with lesions at the ground line. The complete results of this experiment will not be possible for several years, but it was expected to take records at regular intervals each year.

CHESTNUT EXTRACT CHIPS FOR PAPER PULP.

Spent extract chips from blighted chestnut wood which had been run through the leaches of a tannin extract company, were sent to the U. S. Forest Products Laboratory at Madison, Wisconsin, where experiments are being carried on to determine whether or not these chips can be used in the manufacture of paper pulp.

TESTS IN CO-OPERATION WITH MANUFACTURERS.

In connection with the above mentioned experiment, an attempt has been made to make similar tests in a practical way through co-operation with manufacturers. A small shipment of chestnut chips was made to a company in New York State, to test its value for the manufacture of plaster board. A similar shipment was made to a company in Ohio which manufacturers special machinery for reducing wood, the idea being to test these chips for the production of paper pulp.

BLIGHTED WOOD NOT INJURED.

Careful studies to date have shown decidedly that blighted chestnut is injured very slightly, if at all, for use as lumber. The blight lesions extend to only a fraction of an inch below the bark, and even this portion is taken off in the slabs. To illustrate this fact, small hand samples of blighted chestnut in board shape, have been prepared and distributed to different chestnut users throughout the State.

KINDLING AND FUEL TESTS.

There has always been considerable prejudice against the use of chestnut for fuel, and investigations have shown that most likely this prejudice is to a large extent unwarranted. It was intended therefore, at the time of closing our work, to make practical tests of chestnut for kindling, in comparison with the common kindling woods now in the market.

MOVEMENT OF CORDWOOD.

The movement of cordwood under the special reduced tariff has made an excellent beginning. Several hundred cords have already been shipped, and a number of parties were preparing to ship large amounts when our inspection work ceased. The discontinuance of this inspection work will be a financial disadvantage to many timber owners, who were expecting to take advantage of the special tariff, unless some arrangement can be made to continue such inspection under other auspices.

CO-OPERATION WITH THE U. S. FOREST SERVICE.

A list of pole and tie dealers has been furnished by the U. S. Forest Service. This list is being combined with a corresponding list of wood-cutters prepared by this Commission, the whole to be made out in duplicate, which will be of great use for future workers in utilization in this State.

DEMONSTRATION WORK.

The demonstration and lecture work has continued in charge of Mr. Keller E. Rockey.

LECTURES.

The subjects of lectures include every matter of interest concerning the chestnut blight. At intervals, parties engaged in other lines of operation of the Commission have lectured on topics relating to the particular work they were doing. The most of the lectures were given under the supervision of the State Farmers’ Institute management. The lecturers were as a rule, supervisors of the territory in which the lecture was given, and were, therefore, fully able to give the audience news of the latest local developments, and much valuable information.

Besides farmers’ institute lectures, addresses were made at several normal schools, before county fruit growers’ associations, at the meeting of the Northern Nut Growers’ Association, and also at various meetings of botanical societies, civic clubs, and in colleges and schools.

CHESTNUT BLIGHT EXHIBITS.

Exhibits of specimens and illustrations showing in various ways the operations of this Commission have been installed in the Carnegie Museum, at Pittsburgh, and in the State Museum, in Harrisburg. An unusually large exhibit has been started for the Commercial Museum, Philadelphia, and it was planned to make an exhibit at the Everhart Museum, at Scranton. An excellent display showing the work of the Commission was made in connection with the State Forestry Exposition, at Horticultural Hall, Philadelphia, in May. Much interest was shown in this exhibit by people from all over the State. Many minor exhibits have been made in connection with farmers’ meetings at various places.

DISTRIBUTION OF SPECIMENS.

Several hundred small boxes of specimens of disinfected bark showing the chestnut blight were sent to various addresses all over the State, to be placed on exhibition in high schools and other public places. Photographs accompanied this material to add to its interest and practical value.

FIELD DEMONSTRATION.

Very often in connection with the lectures, particularly at farmers’ institutes, the lecturers demonstrated the actual field work of the Commission in neighboring forest tracts, explaining the nature of the disease, the manner of removal, sanitation, and methods of tree surgery.

CO-OPERATION OF THE PRESS.

In connection with the vast amount of active labor performed in field work, pathological research work, chemical and insect investigations, etc., in the effort to control the chestnut tree blight, the press of Pennsylvania proved a most valuable ally in constantly acquainting timber owners and the public in general with the symptoms and characteristics of this comparatively new, but extremely destructive tree pest.