Spatiotemporal variation in acorn production and damage in a Spanish holm oak (Quercus ilex) dehesa

Abstract

Aim of study: There is a lack of knowledge about spatio-temporal patterns of acorn production in dehesas, especially regarding the influence of different agents causing acorn damage. We examined the spatial and temporal variability on acorn production and damage in four stands within a dehesa farm in 1997, 1998 and 1999.Area of study: The study was carried out in a 1800 ha dehesa farm of Cáceres province, western Spain. Material and methods:Acorns were sampled by means of seed traps placed in the canopy of six holm oak trees per stand. Acorns collected were counted and assessed for damage by Curculio weevils, Cydia moths and the bacterial pathogen Brenneria quercina.Main results: Mean acorn production for the whole study period was 44.60 acorns m -2 , which did not vary significantly either among stands or among years. The variability among individual trees was very high (0-300 acorns m -2 ). The rate of infestation by Curculio was 7.64 ± 10.72%, by Cydia was 1.76 ± 3.33%, whereas 10.29 ± 16.12% of acorns were infested by Brenneria. We found no significant spatial differences, but the rates of acorn loss by insects varied among years. These rates were independent of annual acorn production and there was no correlation among damages by different pests, except between Curculio and Cydia in two crop years.Research highlights: It can be concluded that acorn crops are synchronized at the within-farm level and that the temporal variation in acorn damages can be independent of crop size.

Influence of temperature on germination ofQuercus ilexinPhytophthora cinnamomi,P. gonapodyides, P. quercinaandP. psychrophilainfested soils

“…Holm oak ( Quercus ilex ) is the most common tree species in Spain. The dehesa forest, characterized by scattered Q. ilex and Q. suber trees and a pasture of herbaceous annual and perennial species, is the most widespread agroforestry land‐use system in Europe, covering 3.1 million hectares in the Iberian Peninsula (Perez‐Izquierdo and Pulido, ). Dehesa ecosystems are important forests from both ecological and economic perspectives and were classified priority habitats ‘6310 Dehesas with evergreen Quercus spp.’ in EU Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora.…”

Phytosanitary problems detected in black truffle cultivation. A review

“…S19 [pdf online]). (Perez-Izquierdo and Pulido, 2013). It also produces in species of the genus Quercus, small longitudinal lesions of a few centimetres on the trunk bark which produce exudates, especially during spring and autumn.…”