| Autor: |
Laura E. DeWald, Elke Naumburg |
| Rok vydání: |
1999 |
| Předmět: |
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| Zdroj: |
Forest Ecology and Management. 124:205-215 |
| ISSN: |
0378-1127 |
| DOI: |
10.1016/s0378-1127(99)00067-5 |
| Popis: |
Productivity of graminoid species is known to vary in response to different Pinus ponderosa densities. Specific forest structural characteristics related to these differences remain elusive, yet are important for management objectives that aim at a diverse understory vegetation composition. In this study, we have addressed the effects of P. ponderosa forest structure and light environments on individual graminoid species presence and abundance. Graminoid species presence was positively related to mean diameter of P. ponderosa trees (including seedlings), but presence was poorly related to light characteristics. Larger tree diameters may relate to graminoid species presence through shade intensity because shade under larger diameter trees is less dense. The abundance of small diameter trees indicates past disturbance and exposed mineral soil which may favor some graminoid species over others. Graminoid species abundance measured as basal area cover and plant numbers were more closely related to direct sunlight. Cool-season species performed better on sites with spring/autumn or morning summer sun while the larger plants of warm-season species were on sites with midday summer sun. These results suggest that manipulation of forest structure to maintain stands of large diameter trees in a patchy distribution will create a variety of direct sun regimes needed to maintain a diverse grass understory. This type of forest structure is also consistent with pre-European southwestern P. ponderosa forest conditions. # 1999 Elsevier Science B.V. All rights reserved. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect