Ancient Forest Patches – Gallatin CAC

What are Ancient Forests and why do they need to be conserved?

A forest is considered “ancient” if it has never been entirely opened for agriculture, based on evidence from historical aerial photos and LIDAR scans. They may have been at least partially logged and/or served as forest pasture, so most of our regional ancient forests are not “old-growth,” but, like old-growth, they have been forested since the return of trees after the last glaciation (11,000 years ago).

Agricultural conversion can dramatically alter soils and destroy slow-to-disperse plant populations. Studies (including our own fieldwork) have shown that ancient forests can harbor species that are absent from the secondary forests which have regrown on former farmland within the last 80-120 years. This “post-agricultural” forest makes up most of our county’s forest, especially on the flatland.

Unfortunately, most people do not distinguish between ancient and secondary regrowth, and thus development activities rarely differentiate between these two forest types. ancient forests are often located on relatively inaccessible terrain, such as hilltops/ridges. New building technology means such areas are now increasingly targeted for residential development. Once a parcel is developed, its ancient forest has been destroyed and the ecology of adjacent ancient forest stands may be at greater risk due to fragmentation and edge effects. Once ancient forests are destroyed, they are–by definition–gone forever.

What will we do?

By county-wide mapping of ancient forest remnants, we will learn how much/little of this habitat is left, where it is located, and what the size of these remnants is. By conducting more field research, we hope to document additional differences between ancient forest remnants and neighboring post-agricultural forests. We plan to focus on spring wildflowers, which we have not yet properly documented, because of the timing of our previous botanical surveys; ants, which often have a close relationship with spring wildflowers; and mushrooms, which we formerly did not have the taxonomic expertise in our team to document. There is evidence from other places that the fungal communities are more diverse and abundant in ancient than in post-agricultural forests.

How does Gallatin fit in?

The Hawthorne Valley Farmscape Ecology Program found the nearly 5,000 acres of potentially ancient forests as part of its ongoing, countywide mapping effort, using modern and historical aerial photography as well as Light Detection and Ranging (LiDAR) images to detect if forested land has ever been tilled. The Hawthorne Valley team plans to conduct on-the-ground spot checks to confirm its discovery. Gallatin was it’s pilot town.

Of the total area of 25,374 acres in the town, almost a fifth (4,878 acres) is covered by potentially ancient forests remnants that are larger than 10 acres. As a percentage of town area, Gallatin has the most ancient forest in all of Columbia county.
· there are 62 of these patches in the town
· only one of them is larger than 500 acres
· 14 are larger than 100 acres