Composition and structure of forest ecosystems are associated with physical factors (e.g., moisture, nutrients, and light) and biological factors (e.g., competition between plants and consumption by animals). Disturbances affect plants by altering physical and biological factors, but we often fail to appreciate how long these disturbances continue to influence the ecosystem. Sometimes our only clue to past disturbances may come from characteristics of the forest itself, long after visible signs of the disturbance have faded.
The land-use history of the Holt Research Forest is a case in point. It is bisected by a former property line that separated the “North Farm” from the “South Farm”. The farms differed in many respects, including the amount of land cleared for agriculture and cut for forest products, and the date of farm abandonment. This is reflected by composition and structure of the forest vegetation on either side of the line. For example, spinulose woodfern is far more abundant in the understory of the north, whereas trailing arbutus primarily occurs in the south. See Moore and Witham article published in Environmental History.
The historical development of two forest stands on either side of the line differed. In the northern stand, much of the white pine has big-limbed structure and wide early growth rings indicating that they were established under open conditions. They reached breast height (130 cm) from 1910 to 1930, while the red oak in this stand did not reach breast height until the 1940s. In contrast, the pines and oaks in the southern stand established more or less together between 1910 and 1930. In both stands, periods of light cutting are indicated by abrupt increases in radial growth. Historical census and tax data point to the North Farm being agriculturally (livestock and crops) active into the 1930s. This same data shows the South Farm with few animals and minimal agricultural production but owners with wood processing equipment such as portable shingle mills. This demonstrates that the majority of this property was historically a woodlot. What we observe today reflects these distinct land uses.
This air photo from 1940 illustrates the condition of the property with forest and agricultural lands visible. Yellow lines indicate the current property lines, black lines outlines the study area, blue lines indicate ephemeral streams, and red dots are the location of old foundations. A distinct east/west property line is visible in the middle of the study area, this line still remains visible in photos today.