Influences of Past Land Use
To truly understand why Massachusetts is currently lacking in early-successional habitats, we have to look at how our use of the land has evolved through time.
- Natural Disturbance and Today's Forest
- Native American Impacts
- Agriculture and Fuelwood
- Availability of Habitat Today
Windstorms, icestorms, fire, drought, insect outbreaks, and disease are all forms of natural disturbance that had a tremendous effect on presettlement forests. These disturbances continue to influence our landscape, but many ecologists suggest that they have far less impact on the relatively young and resilient forests of today than they did on the disturbance-prone virgin forests of presettlement times. It will probably take a century or more for today's forests to reach an age and size where natural disturbances will create openings on a like those found in presettlement forests. Forestlands that are managed to produce renewable wood products will remain relatively resiliant to future natural disturbances.
Even if forests were allowed to mature, the openings created by natural disturbances (typically covering only a few acres or less) are not always large enough to sustain all species associated with early-successional habitats. For example some songbird species require ten or more acres of open habitat to meet their habitat needs.
Not only is the structure of today's forests vastly different from presettlement times, the landscape as a whole is different. Today's New England landscape is dotted with housing developments, industrial parks, roads and utility rights-of-way that fragment the landscape. In the absence of large predators that historically roamed extensive presettlement forests (e.g., wolves and mountain lions), smaller predators (e.g., coyotes and raccoons) thrive in these fragmented landscapes. A high predator population, in turn, increases the probability of predation on wildlife occupying the small habitat patches resulting from landscape fragmentation. For these reasons, large human-maintained early-successional habitats can offer the best opportunity for maintaining all of the native wildlife species associated with these habitats.
Accounts of early explorers tell of Native Americans' use of fire to clear and cultivate agricultural land. Evidence supports the theory held by many land use historians that Native American populations in New England were much larger than was traditionally thought. Pre-Columbian figures estimate a density of 4.0 - 5.5 individuals/square mile (i.e., 640 acres) in eastern Massachusetts, including Cape Cod. A relatively large population, a lack of soil improvement efforts, and a relative dependence on agriculture, probably led to the creation of a substantial amount of open land and early-successional habitat. Cleared land estimates range from 2-5% - approximately 25,000 - 62,500 acres - in eastern Massachusetts. In fact, two early travelers described land inhabited by Native Americans around the Taunton River area of southeastern Massachusetts as being mostly cleared.
"Thousands of men have lived there, which dyed in a great plague not long since; and pitty it was and is to see, so many goodly fields, & so well seated, without men to dresse and manure the same."
- Bradford and Winslow (1622)
Fires were not only used to create and maintain agricultural fields but also to drive game. In using fire, many fire-adapted natural communities, such as grasslands and scrub oak barrens were maintained. However, as Europeans settled the New World, a philosophy of fire suppression predominated. This well-meaning philosophy evolved to protect personal property. However, it also led to the build up of fuels, which exacerbated many wildfires, including the fire of 1957, which burned 15,000 acres in two days in Plymouth County. Decades of fire suppression also degraded many fire-adapted natural communities and the quality of habitat required by many early-successional wildlife species.
Fields abandoned by a decimated Native American population were among the first sites settled by Europeans since they were already cleared for farming. As more settlers arrived, forestland was cleared to meet the increasing demand for agriculture, timber, and fuelwood.
By the mid-1800's, 60-80% of the land in New England was cleared for agricultural production. Cropland left fallow to recover its fertility and cleared pastureland provided a substantial amount of early-successional habitat in the form of grassland and mixed shrubland/grassland. However, with the exception of river valleys, the land was poor or mediocre at best for farming. When vastly richer farmlands opened up in the Midwest, a large number of New England farmers migrated west. Farmers also migrated to the industrialized cities as opportunities for higher wages were found. For these and other reasons, many New England farms were abandoned in the late 1800's.
A second wave of farm abandonment occurred in the middle part of the 20th century, and only a little over 5,000 farms remain in Massachusetts today.
Fuelwood production also contributed to early landclearing activities. An eighteenth century family had to maintain a 40-120 acre woodlot to produce the 20 - 60 cords of wood needed each year. Additionally, prior to the adoption of coal, fuelwood was used to power steamboats and railroads, and was used in the manufacture of iron, brick, tile, and salt. Railroads and steamboats together accounted for the consumption of nearly three million cords of wood in 1879. The manufacturing industry consumed over four million cords in the same year. As late as 1885, over 70% of Massachusetts' forests were less than 30 years old. However, as people and industry relied more and more on fossil fuels for energy, the use of fuelwood declined. By 1888 fuelwood consumption in southern New England dropped to 7 cords/household/year.
As abandoned agricultural fields and fuelwood lots started to succeed to forest, they provided optimal habitat for early-successional species for the first 10-20 years. As forest succession continued, the habitat became more suited for forest species such as ovenbirds, scarlet tanagers, and banded hairstreak butterflies.
Today, Massachusetts' landscape is dominated by maturing forests. The habitat composition of MassWildlife's system of Wildlife Management Areas (WMA's) can be used as an indicator of the maturity of Massachusetts' forests. Ninety-two percent of MassWildlife's 90,000 acres is forested. It is estimated that 80% of the forest is in sawtimber, while 19% is in sapling and pole sized trees, and only 1% in seedling trees. Only about 7% of MassWildlife lands occur as non-forested habitat such as open wetland or abandoned field. A maturing forested landscape coupled with the residential and commercial development of much of the remaining abandoned agricultural land are taking a toll on early-successional species.
US Forest Service figures show a dramatic decreasing trend in the amount of pole, and sapling/seedling forest from 1972 to 1998.
A distibution of 10% seedling forest, 30% sapling/pole, and 60% sawtimber is desired to maintain populations of all native wildlife species.