Pinus greggii (N) Growth Areas and Yield Estimation

Populations of Pinus greggii are native to two geographical regions in Mexico, viz. a northern population (N) and a southern population (S). In their natural habitat, P. greggii stands from the southern population grow at high altitudes of 1 250 - 2 350 m, where they receive > 1 400 mm rainfall per annum (Dvorak, 2003).This species is, therefore, cold tolerant, but less hardy than P. greggii (N). It is also more drought tolerant than P. patula (Dvorak, 2003). P greggii (S) should, therefore, be established on sites which are too dry for P. patula. Following wide ranging provenance and progeny tests which were carried out in Brazil, Columbia, New Zealand, Zimbabwe and South Africa since the 1980s, the wood of P. greggii (S) has been found to have properties very similar to those of P. patula in terms of density, and it is acceptable for mechanical pulp as well as having excellent structural quality for saw timber (Dvorak, 2003).格雷戈里松（Pinus greggii）的种群天然分布于墨西哥的两个地理区域，即北方种群（N）与南方种群（S）。在自然生境中，南方种群（S）的格雷戈里松林分生长于海拔1250~2350米的高海拔区域，该区域年降水量超过1400毫米（Dvorak, 2003）。该树种具备耐寒性，但耐寒能力弱于北方种群（N）的格雷戈里松；同时其耐旱性强于帕特鲁拉松（Pinus patula）（Dvorak, 2003）。因此，南方种群（S）的格雷戈里松适宜栽植于对帕特鲁拉松而言过于干旱的立地条件。自20世纪80年代起，研究人员在巴西、哥伦比亚、新西兰、津巴布韦与南非开展了大范围的种源与子代测定试验，结果显示南方种群（S）的格雷戈里松木材密度与帕特鲁拉松极为相近，其材质可用于机械浆生产，且作为锯材拥有优异的结构性能（Dvorak, 2003）