Our Forest Studies

 

 

 Tree Identification

 Evening Plant Study Laboratory

Plant Studies and Methods

The east to west transect line is placed in position by faculty and student assistants prior to the start of camp. Its 500 foot length crosses all three associations and provides the reference points needed for the plant work. The line itself is simply a stout cord attached to stakes driven into the ground. Flags, placed every 10 feet along the line, identify the locations where data are to be collected. The individual flags are marked by letter, A to Z and AA to ZZ. The system of sampling and record keeping we use is adapted from the publications of Jackson (10) and Brower (11).

Dominant trees are sampled in pairs along the transect line. At a flag the team first selects the closest tree that is least 10 cm in diameter or greater. This is tree number one. A member of the team then stands at the flag and faces tree number one while raising his/her arms straight out to the side. The arms form a line perpendicular to the line of sight. Another team member then selects a second tree (10 cm or greater) that is behind this perpendicular line and is closest to tree one. This is tree number two. After tree pairs are selected other team members measure the distance between the two trees and the breast high diameter of both trees. Lastly, each tree is identified and all of the information is recorded in the dominant tree data table. This procedure is repeated until all of the team's assigned sample sites have been visited.

Seedlings and saplings are counted and identified during a second visit to the transect line. Teams start at an assigned flag and count the number of seedlings (trees less than 1 meter high and less than 10 cm in diameter) that touch or overhang the transect. Counting continues until the next flag is reached. Each seedling is identified and the number of each seedling type is recorded in the seedling-sapling data table. Saplings (trees greater than 1 meter high and less than 10 cm in diameter) that touch or overhang the transect are counted next. Again, each sapling is identified and the number of each kind is recorded in the data table. This procedure is repeated for each of three assigned transect intervals.

Non-woody plants (grasses), shrubs, vines, ferns, mosses, lichens and litter are sampled during a third visit to the transect. Teams are directed to a specific flag by their instructor. At the flag, the team members walk in a perpendicular line 5 meters south. At this point a meter stick is placed on the ground parallel to the transect line. The study area includes the space 10 cm on each side of the meter stick. Plant types within the space are counted and their height, aerial intercept and basal intercept are measured. Grass clumps are treated as one individual plant. Litter depth is measured at the 50 cm mark of the meter stick and the composition of the litter is recorded. Student observers also note the length of the litter and the length of the bare ground along the meter stick. This procedure is repeated several times by moving the meter stick ahead 1 meter.

Tree height and ground slope information is also collected between the reference points along the transect line. Later, this new data along with that already at hand is used to construct a forest profile sketch. Tree height is measured indirectly using a hypsometer. Slope (rise/run) is calculated from the rise of ground elevation along a 10 meter length of cord. Data samples are obtained from each interval of the transect line.



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