Many inputs make a Forest and Land Management Plan

The Town of Thetford owns roughly 575 acres of land divided among four parcels. The majority of the land is forested. Historically most, if not all, of it had been cleared for agriculture, particularly during the Vermont sheep-farming period that peaked in the 1850s. About 80% of Vermont was deforested for sheep at this time, with long-term consequences that are not fully understood. However, it is likely that soil productivity was impaired for decades, if not a century, by wholesale tree removal and inappropriate farming practices. 

With the abandonment of sheep farms in the later part of the 1800s, forests began to re-grow, but rather than the original forests of diverse tree species across a wide range of age classes, what came back were trees all of the same age, with a species composition that was skewed toward white pine because its seeds were able to persist in the soil. While white pine became dominant in many areas, it was often not well-suited to those environments. Today, close stands of spindly pines with thinning foliage and fungal ailments bear testament to that fact.

Another factor that increasingly threatens the future of these latter-day forests is the ever-growing abundance of non-native, invasive plants. Bush honeysuckle was introduced in the 1800s as an ornamental and was favored for erosion control and wildlife cover starting in the 1960s. It was planted for several decades before its horribly invasive nature became apparent. Buckthorn, another forest invader, has a similar history. Favored ornamentals like barberry and the popular Burning Bush are also invasive. Efforts to ban the sale of these plants in Vermont met resistance from the horticultural industry, although they are banned now. Flower garden escapees like goutweed, a green revertant of the popular groundcover Snow-on-the-Mountain — aka Variegated Bishop's Goutweed or ground elder still available at online plant nurseries — are rapidly consuming what was once woodland wildflower habitat.

The parcels that the Town acquired in the late 1990s to early 2000s had been logged at least once, probably twice, by previous owners and are infested by invasives in some places. In 2008 the Town approved a management plan for these parcels, leading to two significant timber harvests on the Hughes Forest and the Town Forest. These were preceded by efforts to reduce invasive plant numbers because logging opens up the forest and lets in sunlight that causes fast-growing invasive plants to explode and out-compete native tree seedlings. Unfortunately, Town budget limitations did not permit actual eradication. This can take many years because seeds of invasive plants are present in the soil, waiting to germinate. 

The 2008 Management Plan has now expired, and the Thetford Conservation Commission was tasked with replacing it. The original plan had been written by a professional forester and included extensive plant species inventories. It seemed necessary to again engage a forester. Rather than hire a private forester at some expense, the Commission approached Dave Paganelli, the County Forester, whose mission is to help landowners with forest management and stewardship and to provide some level of technical assistance. Dave kindly agreed to walk the parcels, provide an update on the forest conditions, and write a draft plan. 

The Conservation Commission was mindful that a new Management Plan should reflect the Town Plan, the guiding document that provides the basis for land use. Thus the Town Plan was scrutinized, and it was noted that it begins with a Declaration of Climate Emergency including the wording "Town government must work with the citizens and organizations of the town, as well as regional and state organizations, to cut CO2 by 45% by 2030."  Other wording addresses the natural world and includes directing the Town to "encourage forest stewardship techniques that promote the establishment of mature forests with a median canopy age of 150 years … preserve flood storage capacity … control invasive plants on public lands" and "develop strategies that protect both common and rare species."

In response to this information and many other discussions, the Commission developed a cross-referenced table of priorities for the new Management Plan. 

Dave found these guidelines helpful to the process of preparing a draft plan. The Commission also obtained public input through a survey that was distributed at Town Meeting, and the responses from over 70 residents were taken into consideration.  

The resulting Management Plan is a blend of Dave's draft and the writings of two Commission members who are trained foresters. The objectives of the new Plan incorporate new information while building on the objectives of the 2008 Town Lands Management Plan:

1. Enhance forest-based carbon sequestration and storage to mitigate the effects of climate change.
2. Minimize the likelihood of flood damage by maintaining the ability of the landscape to retain water.
3. Foster biodiversity to help maintain ecological functions and enhance ecosystem resilience.
4. Conserve large forest tracts, especially with old growth-like habitat suitable for interior forest wildlife.
5. Maintain groundwater and surface water quality for improved public and aquatic health.
6. Maintain and create recreation opportunities for people of all ages in Thetford.
7. Support local production of wood products through sustainable forest management.
8. Minimize soil erosion and subsequent sediment transport.
9. Protect cultural and historical sites from damage.
10. Preserve the character of the Thetford community and natural environment.
11. Protect rare, endangered, and keystone species through habitat preservation and other means.
12.  Protect wetlands.
13.  Control non-native invasive species.

The Plan also places a new emphasis on forest resilience to climate change. Even-age forests with little species diversity are more likely to succumb to severe weather events and disease outbreaks, because most trees are the same species or a similar size.  Forests of multiple ages and sizes of trees incorporating many different tree species, as exemplified by old-growth forests, are far more resilient.

The writings of Chittenden County Forester and author Ethan Tapper, who trained with Dave Paganelli, expound on this forestry approach. 

To quote Ethan: "Many people think of a well-managed forest as evenly-spaced, uniform trees with a completely bare understory. This couldn’t be farther from the truth.  Old growth forests are what most people would call “messy,” with some large, ancient trees but also trees of all sizes and ages, dead standing trees (“snags”) and a lot of dead wood on the forest floor. … While we can’t make old growth appear overnight, we can manage forests for old growth-type conditions. This includes encouraging the growth of multiple ages of trees and modeling our management on the way that forests naturally grow and develop. ‘Uneven-aged management’ supports irregularity and diversity in the forest, harvesting individual trees and small ‘groups’ or patches of trees, which simulate small-scale natural disturbances."

And, as stated in the new Town Lands Management Plan, "While active (tree) harvests decrease how much carbon is currently stored, they can improve the long term ability of the forest to sequester and store carbon by accelerating future overall growth (i.e. sequestration) and improving resiliency (diverse species of trees of many different ages … Resilient forests are more likely to successfully adapt to climate change while also maximizing the potential for long-term carbon storage, by attaining old growth-like conditions."

The presence of invasive plants will mean control measures will have to be implemented before any trees can be cut. Follow up and monitoring will be needed to ensure that the desired effects — regrowth of a diversity of tree species — is achieved rather than a monoculture of honeysuckle. We thank the Conservation Commission for their continuing vigilance on this front.

Photo credit Li Shen