Why is Ecology Monitoring Important?
- SFMA staff regularly collect forest inventory data
Forests develop over long time periods (80-120+ years) in northern Maine and forest management involves thinking about the forest ecosystem over a similarly long time line. Managing the forest resource requires knowledge and understanding of the current forest but also how that forest will change over time. Change can happen quickly due to natural events, as in the case of a sudden and violent wind storm that can blow down 10’s or 1,000’s of acres in a matter of minutes, or it can happen over decades or centuries such as species range expansions or contractions due to changes in climate. Change can also happen due to human activities like timber harvesting. As managers we want and need to understand the extent of such changes due to natural and human causes, and their implications for our management goals and activities. In order to evaluate change we must have a baseline against which to compare new observed conditions. In forest systems meaningful comparisons normally require baseline data representing past conditions, often measured in decades for the more subtle changes due to climate.
Continuous Forest Inventory:
- SFMA Monitoring plots and stations
In order to address the need to better understand changes in the forest ecosystem the SFMA has developed a variety of standardized monitoring system. One system, known as a continuous forest inventory, (shown as green crosses on this map) includes measurement of permanent plots where all trees on a 1/5 acre plot are numbered allowing diameters and height measurements of the same trees to be taken on a 10 year cycle. This type of information helps managers know how fast the forest is growing and the rate at which disturbance events (like harvest or wind) cause trees to die. This system improves our understanding of changes in the forest ecosystem due to natural events and agents, but also the effect of management activities like harvest on species composition and annual volume growth. These observations are used to improve the application of silvicultural treatments like those described in the Silviculture section of this website.
Temporary Forest Inventory:
In addition to the network of permanent forest inventory samples SFMA staff sample stand conditions across the SFMA with non-permanent (temporary) samples designed to provide a snapshot of forest conditions in that location at that time. These samples survey overstory trees and saplings. Transects are used to sample quantities and origins of dead wood on the forest floor. Sampling is generally conducted after an area has received a silvicultural treatment and one a periodic basis to ensure that inventories do not become outdated (less than 15 years between inventories of the same area. Data is collect in reserve areas as well as riparian management zones. Even in those these areas that may not receive a harvest, the stand composition and structures present provide important information about wildlife habitat and enable the comparison between operational areas and no harvest reserves. Much of this data forms the basis for periodic management plan updates and forest modeling exercises intended to inform the scheduling of management activities.
- Figure 4 Water temperature measurements
from data logger in Murphy Brook
Two other systems are employed to monitor general forest ecosystem conditions. A system of temperature measuring devices record water and air temperatures at specific sites throughout the SFMA. Data like that shown here for Murphy Brook in 2011, provide managers with a baseline against which to compare future measurements to evaluate the influence of management actions on riparian systems and/or effects of changes in climate.
Amphibian Monitoring Stations:
- Figure5: Amphibian monitoring stations
reveal the presence of species
like this blue spotted salamander
A network of sampling stations is checked regularly during the summer to collect data on the presence of forest dwelling salamander species (figure 5). Amphibian species like salamanders are believed to be sensitive to changes in forest conditions and therefore may serve as valuable indicators of forest health. Like the temperature data these measurements will provide future managers with a baseline against which to compare their measurements and assess changes in the forest ecosystem.