Reproductive ecology and allometry of red pine (Pinus resinosa) at the northwestern limit of its distribution range in Manitoba, Canada

Abstract

Red pine (Pinus resinosa Ait.) has been described as a poor seed producer at its distribution range limit; however, few studies have verified this claim or have examined the factors influencing the reproduction of the species. In 2000, data were collected from 60 trees growing in Manitoba at the extreme northwest limit of the natural distribution range for this species. Cones per tree were counted and samples weighed and measured. Likewise, seeds per cone were counted, measured, weighed, and tested for germination. Correlation and regression analyses compared measured characteristics among cones, among individual trees, and among portions of tree crowns (north, west, south, and east portions). Cone abundance among individual trees was significantly and positively correlated with stem diameter and with basal area increment from 1 to 4 years preceding cone maturation. Cone size and fresh mass and seed abundance, mass, and germination were not significantly correlated with individual trees or crown portions; however, seed number per cone and seed size were found to be significantly and positively correlated with cone size. Germination success in red pine increased with seed mass to a certain threshold value, beyond which more than 80% of the seeds germinated no matter what their mass. Our data for 2000 and field observations for 1999 and 2001 showed that red pine at its northwest limit of distribution range produced numerous cones and viable seeds.Résumé : On a longtemps considéré que le pin rouge (Pinus resinosa Ait.) produisait peu de graines à la limite de son aire de répartition. Peu d'études ont toutefois confirmé cette généralisation ou examiné les facteurs influençant la reproduction de l'espèce. En 2000, nous avons échantillonné 60 arbres croissant au Manitoba à la limite nord-ouest de l'aire de répartition de l'espèce. Les cônes ont été dénombrés et des échantillons mesurés et pesés. De plus, les graines ont été comptées, mesurées, pesées et des tests de germination réalisés. À l'aide d'analyses de corrélation et de régression nous avons comparé les caractèristiques des cônes, des arbres et des portions de courronne, divisées selon leur exposition nord, ouest, sud et est. Les analyses montrent que l'abondance des cônes par arbre est significativement et positivement corrélée au diamètre de la tige, à hauteur de poitrine, ainsi qu'à l'accroissement radial pendant les années précédent la maturation des cônes. La taille et la masse des cônes ainsi que l'abondance, la masse et le taux de germination des graines ne sont pas significativement corrélés aux variables décrivant les arbres ou les portions de couronne. Le nombre et la dimension des graines sont toutefois significativement et positivement corrélés à la taille des cônes. Le taux de germination est significativement corrélé à la masse des graines, jusqu'à un seuil critique au-delà duquel plus de 80% des graines ont germé, indépendament de leur masse. Nos données pour l'année 2000 et nos observations pour les années 1999 et 2001 montrent qu'à la limite no...

Stand, tree and crown variables affecting cone crop and seed yield of Aleppo pine forests in different bioclimatic regions of Tunisia

“…This may suggest that due to light competition, neighbouring trees can reduce the rate of light received by dominated and suppressed trees of the stand. Similarly, Sutton et al (2002) also found that red pine (Pinus resinosa Aiton) trees with larger CrS growing in Canada produced higher cone crop.…”

“…Croker et al (1975) demonstrated that a tree with large crowns growing in open stands was the best cone producer. Sutton et al (2002) explained this situation showing that larger crowns had higher photosynthetic carbohydrate reserves to allocate into the fructification phenomena. In the present study, crown traits dominate all other tree dimensions, including DBH and total height, for predicting the cone number and seed mass per tree.…”

“…Aleppo pine carries two types of cones, non-serotinous and serotinous cones (Goubitz et al, 2002), allowing a strategy for a long time seed conservation and Colinas, 2007;Carrasquinho et al, 2010), in addition to the tree crown size (Croker et al, 1975;Sutton et al, 2002). But there are no specific studies linking, on one hand, tree crown variables and cone number, and in the other hand, cone number per tree and seed mass per tree.…”

Effects of structural retention harvesting on seed production and seed characteristics of old-growth eastern white pine (Pinus strobus L.) stands in northern Ontario

“…More open-grown or widely spaced trees may also produce larger numbers of cones and seeds (Stiell 1971, Sutton et al 2002, Krannitz and Duralia 2004, provided spacing is not so wide as to increase self-fertilization (Smith et al 1988, Mitton 1992, Rajora et al 2002. In 80-year-old white pine stands, higher total seed production in areas of intermediate (28 m 2 ha -1 ) compared with high (43 m 2 ha -1 ) basal area was attributed to smaller crowns and fewer cones per tree where density was higher (Graber 1970).…”

Dynamique de la régénération des pins rouges (pinus resinosa) après feu en Mauricie, Québec /

“…Le pin rouge est un faibie producteur de graines (Anonymous 1948;Cayford 1964 ;Van Wagner 1971 ;Stiell 1988 ;Bergeron & Brisson 1990 ;Sutton et al 2002). La régénération des pins est reliée aux années semencières (Roberts 1989).…”