Pinus taeda Growth Areas and Yield Estimation

Pinus taeda also commonly known as loblolly pine, is native to North America. Of the three main species of pine grown in South Africa, viz. Pinus patula, P. elliottii and P. taeda, the latter is the most demanding in respect of climate and soil requirements (Smith, 1998). Optimally, P. taeda requires a MAP > 950 mm, although it can be grown with lower rainfall where temperatures are also relatively lower (Smith, 1998). The species is, however, sensitive to drought. Pinus taeda requires mean annual temperatures ≥ 13 degree Celsius, with July (mid-winter) mean temperatures > 8 degree Celsius, but with January (midsummer) means < 26 degree Celsius (Smith, 1998). While resistant to hail, P. taeda is very prone to snow. Climatically optimum growth areas for Pinus elliottii have been defined in the ICFR`s Forestry Toolbox (Kunz, 2004), by mean annual precipitation (MAP) and mean annual temperature (MAT), as illustrated in This figure also shows the climatic conditions under which suboptimum growth would take place because conditions may at times be too cold and damage from snow occurs, or because occasional drought may occur. Optimum and sub-optimum growth areas of P. elliottii were mapped by applying these criteria to the one arc minute (1` x 1` of a degree latitude/longitude) databases of MAP (Lynch, 2004) and MAT (Schulze and Maharaj, 2004) for South Africa. Using Smith`s (1994) rule based approach and considering only his climatic criteria and not soil or management factors, Pinus elliottii yield estimates were done.