Introduction
In much of the southeastern U.S., post-European settlement land use practices, especially fire exclusion, have led longleaf pine (Pinus palustris Mill.) replace to loblolly pine (Pinus taeda L.) today (Annual Report 2007) in Fort Benning, Georgia, U.S. It was also reported that loblolly pine forests at Fort Benning currently provide important habitat for the endangered red-cockaded woodpecker (RCW, Picoides borealis), depending on for nesting or foraging. However, loblolly pine stands are suspected to decline. Eckhardt and Menard (2008) investigated that loblolly pine decline typically occurs on well-drained soils, which dominate Fort Benning's upland pine sites. Forest managers now need to restore loblolly pine stands to longleaf pine stands and protect RCW from disappearing at the same time. Longleaf pine is a shde-intolerant species, which means they need canopy gap to have sunglight enough and grow up. However, we cannot do clearcut loblolly pine stands to give space for restoring longleaf pine. Currently loblolly pine provides RCW with habitats, therefore, we need to decide which loblolly pines are good to be cut and which loblolly pines are healthy using visualized symptoms of declining.
The annual report (2007) on managing loblolly pine stands to restore longleaf pine for RCW habitat (USDA Forest Service) stated some of forest decline symptoms. Specifically, based on condition, a stand will be classified as in decline if the canopy foliage biomass is less than 10% of the healthy canopy foliage biomass per unit area over a spatial extent of 1 ha, and a stand in decline shows evidence of continuous decreases of canopy foliage biomass to less than 10% of the expected (for a healthy forest on similar site index) canopy foliage biomass within 5 years.
In addition, measurements of tree crowns have been used extensively as indicators of the health and vigor of forest trees (S.J. Zarnoch et al, 2004). It was reported that when natural or anthropogenic stresses impact a forest, the first signs of deterioration are often observed in the tree crowns. Specifically tree crowns have an important role in the regulation of solar energy, nutrient cycling, precipitation distribution, and moisture retention of a forest (S.J. Zarnoch et al, 2004). Analysis of foliage nutrients has been used as an aid in determining the nutritional condition of forests for decades (I.K. Morrison, 1985). J. Neil Cape et al. (1990) conducted a research on the nutritional status of Picea abies across Europe and its relationship with forest decline. It was reported that at sites with trees having ‘poor’ crown condition, there were significantly smaller concentrations of Mg and Ca, and larger concentration of K in 2-year-old foliage from ‘poor’ trees, compared with adjacent ‘good’ trees (J. Neil Cape et al, 1990).
The objective of this project is to find out that crown condition is a reliable indicator to detect forest declining and to be able to be used to decide individual tree's health.
As a reponse variable I used vigor class, and predictor variables I chose foliar nutrients, 100 needles weight, DBH, and tree height. The expected result is that vigor class represents tree's health. If my hypothesis is true, forest managers could use vigor class as an easy tool to decide cut or no-cut loblolly pine for the restoration project.
The annual report (2007) on managing loblolly pine stands to restore longleaf pine for RCW habitat (USDA Forest Service) stated some of forest decline symptoms. Specifically, based on condition, a stand will be classified as in decline if the canopy foliage biomass is less than 10% of the healthy canopy foliage biomass per unit area over a spatial extent of 1 ha, and a stand in decline shows evidence of continuous decreases of canopy foliage biomass to less than 10% of the expected (for a healthy forest on similar site index) canopy foliage biomass within 5 years.
In addition, measurements of tree crowns have been used extensively as indicators of the health and vigor of forest trees (S.J. Zarnoch et al, 2004). It was reported that when natural or anthropogenic stresses impact a forest, the first signs of deterioration are often observed in the tree crowns. Specifically tree crowns have an important role in the regulation of solar energy, nutrient cycling, precipitation distribution, and moisture retention of a forest (S.J. Zarnoch et al, 2004). Analysis of foliage nutrients has been used as an aid in determining the nutritional condition of forests for decades (I.K. Morrison, 1985). J. Neil Cape et al. (1990) conducted a research on the nutritional status of Picea abies across Europe and its relationship with forest decline. It was reported that at sites with trees having ‘poor’ crown condition, there were significantly smaller concentrations of Mg and Ca, and larger concentration of K in 2-year-old foliage from ‘poor’ trees, compared with adjacent ‘good’ trees (J. Neil Cape et al, 1990).
The objective of this project is to find out that crown condition is a reliable indicator to detect forest declining and to be able to be used to decide individual tree's health.
As a reponse variable I used vigor class, and predictor variables I chose foliar nutrients, 100 needles weight, DBH, and tree height. The expected result is that vigor class represents tree's health. If my hypothesis is true, forest managers could use vigor class as an easy tool to decide cut or no-cut loblolly pine for the restoration project.
