Structural patterns and biodiversity in burned and managed Aleppo pine stands

Abstract

Increasing anthropic pressure is making forest fires more frequent in the Mediterranean Basin and therefore affecting the response of native flora and fauna. Two large fires occurred in summer, 1994, in the Southeastern Iberian Peninsula. Aleppo pine, the main tree species, regenerated naturally after the fire. In this study we are interested in strategies for maximizing Aleppo pine tree recovery and conservation of its ecosystem. We performed thinning and pruning in the pine tree stands 5 and 10 years after the fire and took measurements on structural patterns and plant diversity using several indices. In addition, we measured macro-lichen and faunal diversity indirectly. Results show significant differences between treated-burned plots and untreatedunburned plots. The plots thinned 10 years after the fire and the unburned plots (mature stands) showed a regular, non-aggregated distribution and a low diameter differentiation. Also, these plots showed similar plant diversity values. The silvicultural treatments did not significantly affect the fauna and lichen index values. The high intensity of thinning and late pruning applied to young Aleppo pine stands improved the structural pattern and plant diversity.

Growth and structure of a young Aleppo pine planted forest after thinning for diversification and wildfire prevention

“…This preventive approach may be crucial in Aleppo pine forests, as they usually have a low crown height (3-6.5 m) which increases the risk of crown fire initiation even under moderate burning conditions (Mitsopoulos and Dimitrakopoulos, 2007). However, differences in TD3 among thinning regimes were not very notable, as other authors have also reported (Moya et al, 2009). TD3 decreased with time in all cases, in agreement with previous references (Crecente-Campo et al, 2009), but the decrease we observed was greater in heavier thinnings.…”

“…In contrast, in a long-term thinning experiment in northeast China, thinning from below was found to produce some departures from the random distribution of trees observed in control plots (Lei et al, 2007). In a postfire regenerated Aleppo pine stand in south-eastern Spain, early thinning was found to increase the initially low CE values (0.14-0.68) and promote a non-clustered tree distribution (Moya et al, 2009). Further research using other thinning methods in MPCF could provide a useful contrast to the results we obtained in tree distribution through random thinning.…”

Post-Fire Seedling Recruitment and Morpho-Ecophysiological Responses to Induced Drought and Salvage Logging in Pinus halepensis Mill. Stands

“…According to our findings, this situation was critical in the first months after a fire since plant coverage prevents soil erosion, flooding and runoff [48], while it can significantly affect growth and ecophysiological variables during longer periods [41]. Some morphological or ecophysiological parameters can also vary depending on forest management [49], intraspecific competition (seedling density, spatial distribution, and size of individuals) [50], and seasonality [45].…”

Effects of pre-commercial thinning on growth and reproduction in post-fire regeneration of Pinus halepensis Mill

“…However, the benefits and risks of thinning to reduce sapling density after a fire are not well-defined. Positive effects of thinning in post-fire regeneration of P. halepensis have been observed for cone production, structural pattern and plant diversity (González-Ochoa et al 2004;De las Heras et al 2007;Moya et al 2009); but negative effects have also been observed after treatment, such as higher levels of defoliation from Pachyrhinus squamosus Kiesenwetter (González-Ochoa et al 2002). Moreover pre-commercial thinning influenced also allometric equations and carbon partitioning in P. halepensis regenerated after fire (De las Heras et al 2012).…”