Treesearch

A newly devised apparatus using pressure to inject fluids into trees was used to inject solubilized benomyl into elms, oaks, and maples. In October and November, injections were made into the outer two annual rings of sapwood at points 2 to 3 feet above ground line. One to 3 weeks after injection, the trees were sampled; and positive bioassays were obtained from branch tips of some of the elms, oaks, and maples. Injection of benomyl into elms, oaks, and maples may provide protection from infection by fungal pathogens or may provide therapy for diseased trees.

Vacuum pumping of sugar maple trees during the late fall and early winter months is not advisable in northern Vermont. However, fall pumping may be profitable in other areas of the sugar maple range. It is recommended that the weather pattern in a given locale be observed; and if conditions are favorable, vacuum pumping should be tried on a small scale before attempting a larger operation.

A study was made to determine the effect of moisture loss on the weights of red oak sawlogs. The logs, ranging from 9 to 21 inches in scaling diameter and from 8 to 14 feet in length, were dried for a 12-week period. The 21-log sample lost 7.6 percent of the total green sawlog weight. The weight loss for individual logs ranged from 5.3 to 14.5 percent. In general, as log size and weight increased, the percent of weight loss decreased.

Results of this study showed no statistical difference in the quantity or sweetness of sugar maple sap collected from tapholes that were drilled with a variety of tappers running at different drilling speeds

Two methods of using plastic tubing to collect sugar maple sap were tried: aerial lines and ground lines. Unvented spouts were used in both. We found that the sap yields collected from the aerial and ground lines were not statistically different from each other.

Softwood stem cuttings from three mature sugar maple trees were treated with several types and concentrations of growth regulators. Lack of statistical significance was due to extreme variability in tree response: low levels of auxin stimulated rooting in two study trees, while auxins inhibited rooting in the other tree. It is postulated that variations in rooting response may have been caused by corresponding differences in endogenous levels of naturally-occurring auxins.

MULGRES is a computer program source deck that is designed for multiple regression analysis employing the technique of stepwise deletion in the search for most significant variables. The features of the program, along with inputs and outputs, are briefly described, with a note on machine compatibility.

A study of sugar maple tapping indicated that sugar producers can drill a new taphole within 1 inch of an old taphole in a horizontal direction and obtain normal sap and sap-sugar yields.

A study of 114 northern red oak, Quercus rubra, indicated that decay is not serious during the time necessary to produce high-quality saw logs and veneer logs. Two heart-rot fungi, Poria oleraceae and P. cocos, accounted for almost 25 percent of the total decay volume in the study trees. Basal fire wounds, dead branch stubs, and open branch-stub scars were the most important means of entry for decay fungi.

The amount of sugar maple sap that can move through plastic tubing is controlled by several factors. The most important are tubing diameter and slope percent. Estimates are given of the number of tapholes that can be used with combinations of these variables.