Deciduous ForestsINTRODUCTION A deciduous forest, simply described is a forest that is leaflessduring the winter.
Eury species make up this type of forest, meaning that thespecies can tolerate a wide range of conditions.In the extreme northernlatitudes, the growing season is short causing the trees to be leafless themajority of the year. The deciduous forest is subjected to distinct weathercycles and temperature shifts. In this area of the northeast we experience fourdistinct seasons, and for a tree species to thrive it must adapt to the stressescorresponding to each season.Of the three basic types of temperate broadleaf forests, (temperate deciduousforest, temperate woodlands, and temperate evergreen forest) our lab data dealswith characteristics of the temperate deciduous forest. This forest type oncecovered large portions of Eurasia, South America, and North America.
As withmost native forests, they have been cleared so that the land could be used forfarming or residential use. The temperate deciduous forests of North Americawere more diverse than the same type of forests in Europe due to glacial history.Glacial action dumped till as the ice edge retreated, and North Americainherited a fertile soil base.
Soil type is an important factor for whichspecies of trees can thrive in an area. The general dominant tree species fortemperate deciduous forests are Beech, Ash, Oak, and in our region also Tulip,Maple, Birch, and Hickory. Developed forests consist of four layers. The layersare: canopy, sub canopy, shrub, and ground cover.
This layering affect benefitsthe diversity of the ecosystem by providing a rich variety of habitats. It is aresult of adaptation and competition for sunlight and shows the continuingprocess of succession. The stratification of a forest, by intercepting the someof the available sunlight at various locations, also creates micro-climates witha wide range of temperatures and moisture conditions.
The soil composition alsogreatly influences the amount of water that is available to the plant species.The composition of the soil, the various layer development and the nutrientcontent are major factors in the survival of specific species of trees. Climateand soil type are a-biotic factors, meaning they are outside and uncontrollableby the species itself. Insect infestations such as Gypsy moths and disease suchas the Chestnut blight are also a-biotic factors that in a relatively shortperiod of time can severely thin out or destroy a specific species of tree.Itmight just add enough stress to one species, where a competing species will thenout-compete it and then dominate.The cycle of dropping the leaves when the days grow short is vital for thereplenishment of nutrients in the soil.
This litter layer decomposes and returnsorganic material to the trees through leeching and decomposition into the uppersoil layers where they can be reused by re-absorption through the roots.METHODS This lab involved the investigation of a deciduous forest located on theundeveloped portion of the campus. The survey techniques used to collect datafor the vegetation analysis portion of this lab were the quadrant and lineintercept methods.
Using pre-established 25 meter square plots, on oppositesides of a stream, the tree species and sizes were mapped and recorded. Breastheight diameter measurements were made on the canopy and sub canopy trees ineach quadrant. The types of trees found and the number per species was recordedand used to figure which species were dominate. Each quadrant also used a randomline intercept of 10 meters in length to determine the density of the bushcoverage of the quadrants.
A soil analysis of both sides of the creek was alsoconducted to determine the affects of a-biotic conditions on the species…..recorded in the vegetation analysis. Multiple samples of the A1 and A2 horizonswere collected and analyzed using standard screening and drying stages todetermine soil particle size and moisture content.
The measurement of thespecific gravity using a hydrometer while the soil particles are settling out ina flask is used to calculate the percentages of sand, silt, and clay fractionsof the soil samples. These sampling techniques were derived from exercises #14and #40 located in: George W. Cox, Laboratory Manual of General Ecology, seventhedition, W.
C. Brown Publishing, 1996.RESULTS & DISCUSSION The data for this lab was analyzed in stages.In the twocharts provided, the overall differences between the two sides of the forest canbe seen.
The first chart compares the tree species found on each side of theforest and shows the relative dominance.Relative