Trees will be trees…

As much as the unusual weather has attempted to thwart pollination efforts, we have finally entered into the first week of pre-pollination bagging here in Litchfield County. For the most part, the enormous amount of precipitation has put a real “damp”er on the time and accurate estimation of flower maturation. Luckily for the Connecticut chapter, dependable and determined members have kept an even closer eye on flower progress in an effort to determine the right time to bag. From what I’ve been told of seasons past, bagging this year is at least a week (oftentimes more) later than it usually is. In addition, male catkins aren’t maturing at their usual rate, making them unreliable determinants of female flower progress. Alas, I believe we have battled our way through this unfortunate summer and are finally ready for the first step in the pollination process.

On Tuesday, June 30th, two trees in the central part of Litchfield County will be bagged by Bartlett tree experts. Their generous donation of bucket trucks and expert bagging assistance will undoubtedly make the process run smoothly. Bagging female flowers involves removing all surrounding male catkins and leaves so there is no trace of pollen or interference to flower maturation. Small paper bags are gently, yet securely, placed around the female flower and subsequent twig. These bags will remain on the female flowers for the next 3-4 months. Ten to fourteen days after bagging, Bartlett will return to the tree, remove the bags, apply the genetically desired pollen, and carefully replace the bags. After the controlled pollination event, the flowers will mature into seeds with a surrounding, protective burr which will be harvested sometime in October.

: Bartlett bagging a tree in Canaan, CT. Photo courtesy of Gayle Kida.

Bagged female flowers on a Burlington, CT tree. Photo courtesy of Gayle Kida.

The number of bags placed on the trees obviously depends on the number of flowers present on the tree. The general goal is to harvest 100 nuts per tree (producing an adequate breeding line). However, this goal is not always reached in a single season. Since most of the reproductive trees are fairly small and shrub-like, it is fairly common to receive about half the desired amount. The plan is to therefore choose trees that can be pollinated and harvested in two consecutive years (to reach the goal). Each female flower will yield about 3 nuts; however, usually only 2 of these nuts are fertile. In the case of the two trees which will be bagged on Tuesday, it is likely that the trees will get 20-30 bags of about 30 flowers. Then we must hope that the tree not only survives another year, but also is reproductive another year.

The tree I will be managing will likely be ready to bag next week. It is located on the highest elevation range in Connecticut and is consequently well behind the lower elevation trees. This tree will probably not produce 100 nuts this year either, but the tree seems to be in decent health and will likely be around next year.

Female flowers on the Riga Mountain Chestnut tree (highest elevation ridge in CT). The flowers are at the base of the catkins and are almost "cabbage-like." These flowers are at least a week to maturity.

The point of controlled pollination is to simultaneously breed in blight resistant traits with desired American Chestnut traits. Blight resistance is a genetic trait of Chinese chestnuts, but the overall Chinese tree characteristics are inferior to the American characteristics. This year’s Litchfield County trees are all validated American Chestnuts and are sources of desirable American genetics and local adaptability.

Although we’ve come across several setbacks (some trees were unfortunately hybrids and not American, permission for use was not granted, and promising trees refused to develop catkins), we’re hoping for a successful season with the trees we did finally locate as representatives of Litchfield County. Stay tuned!