Charles Lafon

... In the bald ground, some pioneer species were planted, such as Masson pine (Pinus masso-niana), Taiwan acacia (acacia confusa), longleaf ... school of life sciences, sun Yat-sen University, guangzhou 510275, china, +86 20 84039571, lsspsl@mail.sysu.edu.cn), Yi-na Yu ...

Question: Can fire be used to maintain Yellow pine (Pinus subgenus Diploxylon) stands disturbed by periodic outbreaks of southern pine beetle?Location: Southern Appalachian Mountains, USA.Methods: We used LANDIS to model vegetation disturbance and succession on four grids representative of xeric landscapes in the southern Appalachians. Forest dynamics of each landscape were simulated under three disturbance scenarios: southern pine beetle, fire, and southern pine beetle and fire, as well as a no disturbance scenario. We compared trends in the abundance of pine and hardwood functional types as well as individual species.Results: Yellow pine abundance and open woodland conditions were best maintained by a combination of fire and southern pine beetle disturbance on both low elevation sites as well as mid-elevation ridges & peaks. On mid-elevation SE-W facing slopes, pine woodlands were best maintained by fire alone.Conclusions: Our simulations suggest that fire can help maintain open pine woodlands in stands affected by southern pine beetle outbreaks.

Major ice storms are significant forest disturbance agents and natural hazards in eastern North America. Studies of forest damage suggest that ice storm severity varies among topographic positions, but little climatic information is available to evaluate fine-scale variations in ice storm climatology. Our study assesses the utility of tree-ring analysis for identifying fine-scale spatial patterns and long-term temporal variations in the frequency of major ice storms. We looked for ice storm signals in tree-ring chronologies of chestnut oak Quercus prinus L. and black oak Q. velutina Lam. at 2 sites in southwestern Virginia that were affected by known ice storms in 1979 and 1994. Radial growth of these species exhibits a dual response to ice storm disturbance. Trees with substantial canopy loss show reduced radial growth for several years following an ice storm. Other trees display increased growth due to the loss of competitors. We identified thresholds of ring-width increase and decrease that distinguished ice storms from other events, permitting a preliminary attempt to reconstruct ice storm history at each of the 2 study sites. For our Gap Mountain site, ring-width chronologies spanning the period 1914–1998 record apparent signals of major ice storms in 1920, 1979, and 1994. For the Walker Mountain site, our results suggest that during the period 1901–1998 the stand was affected by major ice storms in 1918 and 1994. This study suggests that dendrochronology provides a promising method for understanding fine-scale spatial patterns of ice storm disturbance in hardwood forests.

Abstract Small Footprint LiDAR (Light Detection And Ranging) has been proposed as an effective tool for measuring detailed biophysical characteristics of forests over broad spatial scales. However, by itself LiDAR yields only a sample of the true 3D structure of a forest. In order to extract useful forestry relevant information, this data must be interpreted using mathematical models and computer algorithms that infer or estimate specific forest metrics. For these outputs to be useful, algorithms must be validated and/or calibrated using a sub- ...