Sunday, July 11, 2010

Hemlock Wooly Adelgid - GETT

While in Resource Management, I was also able to spend a couple days with Forestry Tech Randy Krickton. He explained to me the park's cultural landscape rehabilitation plan, along with demonstrating his almost magical ability to name whatever plant I pointed to off the top of his head. During our first day together, he took me to a group of hemlocks the crew was currently spraying for hemlock woolly adelgid.

Cottony egg sacks of HWA

Hemlock woolly adelgid is a severe problem here in our park. Many of our cemetary's hemlocks, as well as some of the trees near the old cyclorama building are currently infested with the sap-sucking insects. These cottony masses on the underside of the branches are full of eggs, which will one day mature into what Forestry Tech Randy described to me as "little crawlers" that will suck the sap from the tree's needles. This causes defoliation of the tree, and if left untreated, will inevitably cause the tree to die.

An infected tree

Trees with HWA have an almost silvery characteristic in their boughs, and all around look sick due to the attack on their needles. The Resource Management team has been working very hard to save our park's hemlocks.

Applying a root soak to the hemlocks

Currently, we're working from the ground up - by root soaking the hemlocks with an insecticide that is toxic to the HWA, but does not harm the tree. As the tree absorbs the insecticide in its root system, it becomes incorporated into the sap. This means that when the HWA crawlers try to suck the sap from the hemlock needles, they get a belly full of poison and drop dead - which is exactly what needs to happen to save the tree. Usually, rain helps in the application process, because it drives the insecticide down towards the roots so that it can be absorbed - but when it's dry (as it has been), manual watering is required.

I didn't get to work with the poisons, as I'm completely unqualified - but I did get to watch and ask questions, which is almost as good. It was interesting for me to get to learn first-hand exactly what goes into managing a landscape. Here at Gettysburg, we try to maintain the historic fields and orchards as they were the day of the battle - and yet, fields will naturally always attempt to return to forest.

Without farmers cutting woodlots for fuel and building materials, and without nearly the amount of farmers working the fields for crops - we have to take a more active, deliberate approach. Part of resource management's job, then, is to approximate the effects of 1860's tree cutting and farming through scheduled forestry activities such as health cuts and invasive species management. It is a job that literally never ends - because while we work 40 hours a week, mother nature never sleeps, and there's always going to be that field-to-forest process to contend with - along with the issue of managing unnatural, man-made issues such as the introduction of exotics and invasive.

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