Tree seedlings respond to both light and soil nutrients in a Patagonian evergreen-deciduous forest
نویسندگان
چکیده
Seedlings of co-occurring species vary in their response to resource availability and this has implications for the conservation and management of forests. Differential shade-tolerance is thought to influence seedling performance in mixed Nothofagus betuloides-Nothofagus pumilio forests of Patagonia. However, these species also vary in their soil nutrient requirements. To determine the effects of light and soil nutrient resources on small seedlings we examined responses to an experimental reduction in canopy tree root competition through root trenching and restricting soil nutrient depletion through the addition of fertilizer. To understand the effect of light these treatments were undertaken in small canopy gaps and nearby beneath undisturbed canopy with lower light levels. Seedling diameter growth was greater for N. pumilio and height growth was greater for N. betuloides. Overall, diameter and height growth were greater in canopy gaps than beneath undisturbed canopy. Such growths were also greater with fertilizer and root trenching treatments, even beneath undisturbed canopy. Seedling survival was lower under such treatments, potentially reflecting thinning facilitated by resource induced growth. Finally, above-ground biomass did not vary among species although the less shade tolerant N. pumilio had higher below-ground biomass and root to shoot biomass ratio than the more shade tolerant N. betuloides. Above- and below-ground biomass were higher in canopy gaps so that the root to shoot biomass ratio was similar to that beneath undisturbed canopy. Above-ground biomass was also higher with fertilizer and root trenching treatments and that lowered the root to shoot biomass ratio. Restricting soil nutrient depletion allowed seedlings of both species to focus their responses above-ground. Our results support a view that soil nutrient resources, as well as the more commonly studied light resources, are important to seedlings of Nothofagus species occurring on infertile soils.
منابع مشابه
Soil–plant relationships and tree distribution in old growth Nothofagus betuloides and Nothofagus pumilio forests of Tierra del Fuego
The evergreen Nothofagus betuloides and deciduous Nothofagus pumilio live close together in Tierra del Fuego. The fact that these two species rarely form mixed forests suggests that the soil factor can contribute to the distribution of two species on a local scale. Most of these forests are undisturbed; therefore, soil characteristics may reflect both the influence of the species and of the dom...
متن کاملAssessment of Nutrient Turnover and Soil Fertility of Natural Forests of Central Western Ghats
This study was undertaken to quantify the nutrient turnover and soil fertility status in the natural forests of Central Western Ghats. Major nutrients such as nitrogen, phosphorus and potassium were analyzed in the litter, both from the samples collected in pre and post monsoon seasons. There was no much difference seen in the values between the two seasons studied in all the three nutrients st...
متن کاملForest Typification to Characterize the Structure and Composition of Old-growth Evergreen Forests on Chiloe Island, North Patagonia (Chile)
The Evergreen forest type develops along the Valdivian and North-Patagonian phytogeographical regions of the south-central part of Chile (38° S–46° S). These evergreen forests have been scarcely studied south of 43° S, where there is still a large area made up of old-growth forests. Silvicultural proposals for the Evergreen forest type have been based on northern Evergreen forests, so that the ...
متن کاملMarkedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient
We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest ty...
متن کاملDistinct Leaf-trait Syndromes of Evergreen and Deciduous Trees in a Seasonally Dry Tropical Forest
In seasonally dry tropical forests, tree species can be deciduous, remaining without leaves throughout the dry season, or evergreen, retaining their leaves throughout the dry season. Deciduous and evergreen trees specialize in habitats that differ in water availability (hillside and riparian forest, respectively) and in their exposure to herbivore attack (seasonal and continuous, respectively)....
متن کامل