The distribution of pine sawfly cocoons (Diprionidae) in Scots pine stands in relation to stand edge and tree base

• Published in: Forest ecology and management Vol. 54; no. 1-4; pp. 193 - 203
• Main Author: Simandl, Jiří
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.1992; Elsevier
• Subjects: Biological and medical sciences; Diprionidae; forest stands; Fundamental and applied biological sciences. Psychology; Hymenoptera; Invertebrates; peuplement forestier; Phytopathology. Animal pests. Plant and forest protection; Pinus sylvestris; Protozoa. Invertebrates; Records, symptoms, damages, economic importance, population surveys; rodales; Europe; Czechoslovakia; Czech Rep., Bohemia; Litter; Insecta; Cocoon; Forest soil; Long term variation; Diprionidae; Pinus sylvestris; Population survey; Pest; Arthropoda; Host plant; Softwood forest tree; Gymnospermae; Coniferales; Spermatophyta; Hymenoptera; Invertebrata; Sampling; Infestation; Population density; Distance
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/0378-1127(92)90012-X

The distribution of cocoons of the sawfly community (Diprionidae) within Scots pine (Pinus silvestris L.) stands was quantified for endemic populations in relation to stand edge and distance from tree trunks on the basis of old and living cocoons that had accumulated for several years in the litter. Pine stands were 40 and 80 years old and located in southern Bohemia (Czechoslovakia). The density of living sawfly cocoons overwintering in the litter was low, 0.25–0.48 m−2, (average 0.37) and comprised 2.7% of 2346 cocoons in the samples. Numbers of cocoons decreased with increasing distance from stand edge with 40.5% of the cocoons near the stand edge, in contrast to 25.1% in the stand. Significant differences in cocoon densities also occurred in stands of both ages examined. The cocoon densities decreased nearly linearly with increasing distance from the host tree trunk. About 37% of the cocoons occurred less than 0.3 m from the tree base. The method of circular samples may be more effective at lower population densities.