Formation and closure of canopy gaps in the rain forest at Nouragues, French Guiana / P.J. van der Meer (1996)

Public ISBD Titre : Formation and closure of canopy gaps in the rain forest at Nouragues, French Guiana Type de document : texte imprimé Auteurs : P.J. van der Meer ; F. Bongers Editeur : Kluwer academic publishers Année de publication : 1996 Collection : Vegetatio num. 126 Importance : pp. 167-177., ill., tabl. graph. réf. Langues : Anglais (eng) Catégories : Autres descripteurs CANOPY GAPS ; CANOPY OPENNESS ; FRENCH GUIANA ; GAP CLOSURE ; GAP FORMATION ; HEMISPHERICAL PHOTOGRAPHS ; RAIN FOREST ; SHALLOW SOILS ; SPATIAL PATTERNS Résumé : Formation and closure of canopy gaps was monitored for three years in 12 ha of primary rain forest at Nouragues, French Guiana. At the first inventory, in April 1991, 74 openings in the canopy >4m2 (sensu Brokaw 1982a) were located; 60 of these gaps were formed before junuary - 1990. B etween January 1990 and december 1993, 5 to 15 gaps were annually formed, opening 0.64-1.33% of the forest canopy each year. Of all gaps, 41% were created by a falling, snapped tree, 34% by a falling, uprooted tree, 22% by a falling branch, and 3% by a falling dead stem. A refined nearest neighbour analysis showed that gaps formed after january 1990 were clustered : uprooting of trees seemed to be related to shallow soils, and relatively many other trees fell when a tree uprooted, independent of the dhb of the uprooted tree. In 37 gaps, canopy openness in the gap centre (determined by hemispherical photographs) was monitored over three years. In 54% of the gaps, canopy openness increased in two successive years. It is reasoned that edges of especially large gaps may frequently be re-disurbed by falling trees or branches. Resultssuggest that gaps have closed after around 15 years. More data are needed to verify this. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151513 Formation and closure of canopy gaps in the rain forest at Nouragues, French Guiana [texte imprimé] / P.J. van der Meer ; F. Bongers . - [S.l.] : Kluwer academic publishers, 1996 . - pp. 167-177., ill., tabl. graph. réf.. - (Vegetatio; 126) . Langues : Anglais (eng) Catégories : Autres descripteurs CANOPY GAPS ; CANOPY OPENNESS ; FRENCH GUIANA ; GAP CLOSURE ; GAP FORMATION ; HEMISPHERICAL PHOTOGRAPHS ; RAIN FOREST ; SHALLOW SOILS ; SPATIAL PATTERNS Résumé : Formation and closure of canopy gaps was monitored for three years in 12 ha of primary rain forest at Nouragues, French Guiana. At the first inventory, in April 1991, 74 openings in the canopy >4m2 (sensu Brokaw 1982a) were located; 60 of these gaps were formed before junuary - 1990. B etween January 1990 and december 1993, 5 to 15 gaps were annually formed, opening 0.64-1.33% of the forest canopy each year. Of all gaps, 41% were created by a falling, snapped tree, 34% by a falling, uprooted tree, 22% by a falling branch, and 3% by a falling dead stem. A refined nearest neighbour analysis showed that gaps formed after january 1990 were clustered : uprooting of trees seemed to be related to shallow soils, and relatively many other trees fell when a tree uprooted, independent of the dhb of the uprooted tree. In 37 gaps, canopy openness in the gap centre (determined by hemispherical photographs) was monitored over three years. In 54% of the gaps, canopy openness increased in two successive years. It is reasoned that edges of especially large gaps may frequently be re-disurbed by falling trees or branches. Resultssuggest that gaps have closed after around 15 years. More data are needed to verify this. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151513

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Spatial genetic differentiation among populations of european beech (fagus sylvatica L.) in western germany as identified by geostatistical analysis / B. Degen (1998)

Public ISBD Titre : Spatial genetic differentiation among populations of european beech (fagus sylvatica L.) in western germany as identified by geostatistical analysis Type de document : texte imprimé Auteurs : B. Degen ; F. Scholz Editeur : Arbora Publishers Année de publication : 1998 Collection : Forest Genetic num. 5(3) Importance : pp. 191-199., 1 graph., 3 tabl., 3 cartes., nb réf. Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Fagus sylvatica Autres descripteurs SPATIAL PATTERNS ; GENETIC DIFFERENTIATION ; GENETIC DISTOGRAMS ; KRIGING ; PERMUTATION TEST ; GENETIC DIVERSITY Résumé : The spatial genetic differentiation among European beech stands in western Germany was analysed by a new method. The genetic structure at 8 enzyme gene loci of lOO sarnpled populations was used as data base. The data represent authors' own results and published data from 8 different studies. For 10 geographic distance classes [h] from 0 to 500 km, the average genetic distance J(h between the populations for each single gene locus, a gene-pool distance J(hk) and the semivariances ,(hk) of genetic diversity Ugam were computed. Significant deviation from random spatial genetic structure was teste by permutation analysis. ln many cases (Lap-B, Mdh-B, Mdh-C and 6Pgdh-C) the mean genetic distance h J between stands with spatial distance up to 200 km was significantly smaller and the genetic distance between stands with geographic distances of 200 and 400 km was significantly greater than expected for random spatial genetic structure. Similar tendencies were found for the gene-pool distance and the semivariances y(hk) of diversity. Kriging, as a method for spatial interpolation, was used to draw synthetic maps of the spatial patterns of allelic frequencies and genetic diversity. The influence of postglacial recolonisation and regeneration with foreign seed material on the spatial genetic patterns are discussed. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=150493 Spatial genetic differentiation among populations of european beech (fagus sylvatica L.) in western germany as identified by geostatistical analysis [texte imprimé] / B. Degen ; F. Scholz . - [S.l.] : Arbora Publishers, 1998 . - pp. 191-199., 1 graph., 3 tabl., 3 cartes., nb réf.. - (Forest Genetic; 5(3)) . Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Fagus sylvatica Autres descripteurs SPATIAL PATTERNS ; GENETIC DIFFERENTIATION ; GENETIC DISTOGRAMS ; KRIGING ; PERMUTATION TEST ; GENETIC DIVERSITY Résumé : The spatial genetic differentiation among European beech stands in western Germany was analysed by a new method. The genetic structure at 8 enzyme gene loci of lOO sarnpled populations was used as data base. The data represent authors' own results and published data from 8 different studies. For 10 geographic distance classes [h] from 0 to 500 km, the average genetic distance J(h between the populations for each single gene locus, a gene-pool distance J(hk) and the semivariances ,(hk) of genetic diversity Ugam were computed. Significant deviation from random spatial genetic structure was teste by permutation analysis. ln many cases (Lap-B, Mdh-B, Mdh-C and 6Pgdh-C) the mean genetic distance h J between stands with spatial distance up to 200 km was significantly smaller and the genetic distance between stands with geographic distances of 200 and 400 km was significantly greater than expected for random spatial genetic structure. Similar tendencies were found for the gene-pool distance and the semivariances y(hk) of diversity. Kriging, as a method for spatial interpolation, was used to draw synthetic maps of the spatial patterns of allelic frequencies and genetic diversity. The influence of postglacial recolonisation and regeneration with foreign seed material on the spatial genetic patterns are discussed. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=150493

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