Collaborative Research: Nutrient co-limitation in young and mature northern hardwood forests

北方阔叶林幼林和成熟林的养分共同限制长期以来，温带森林被认为是氮（N）限制的，但随着时间的推移，空气污染造成的慢性N沉降应减少N限制，理论表明，生态系统生产力应受到多种养分的共同限制。在温带森林系统中缺乏氮与磷限制的实验测试。 本研究将结合联合收割机模拟和实地研究，探讨养分限制与森林生态系统演替的关系。 提高对资源利用的生态系统优化的理解对于森林管理、环境保护和基础科学知识都很重要。平衡的养分循环对维持森林的可持续性至关重要，白色山国家森林的科学家和管理人员将根据拟议研究的结果评估造林做法。 例如，它们的森林管理计划要求从森林获取养分用于再生长的能力方面说明密集采伐的理由。 反馈，如生物增强矿物风化时，营养物质是有限的，显然是相关的，这appraisal.The多元素限制（MEL）模型包括P以及N，碳，光，水，并被应用于模拟演替北方硬木林。在新罕布什尔州的巴特利特实验森林中，在三个年龄（~20年、30年和100年）的复制林分中，在一些林分中仅使用N、在一些林分中仅使用P、在一些林分中使用N+P的营养添加，调查人员将测试资源限制的模式。 该模型预测了更大的地上生产力的反应，N+P比N或P单独。在较老的立场，它预测一个更大的响应N比P此外，但在年轻的立场，该模型表明，从碎屑N的供应应该是足够的创建P限制。

Nutrient Co-limitation in Young and Mature Northern Hardwood ForestsTemperate forests have long been thought to be nitrogen (N) limited, but chronic N deposition from air pollution should reduce N limitation over time, and theory suggests that ecosystem productivity should be co-limited by multiple nutrients. Experimental tests of N vs. phosphorus (P) limitation in temperate forest systems are lacking. This study will combine modeling and field studies to explore nutrient limitation in relation to successional change in managed forest ecosystems. An improved understanding of ecosystem optimization of resource use is important to forest management, environmental protection, and basic scientific knowledge. Balanced nutrient cycling is essential to maintaining forest sustainability, and scientists and managers at the White Mountain National Forest will evaluate silvicultural practices in light of results from the proposed research. For example, their forest management plans require justifying intensive harvest removals in terms of the ability of forests to acquire nutrients for regrowth. Feedbacks such as the biological enhancement of mineral weathering when nutrients are limiting are clearly relevant to this appraisal.The Multi-Element Limitation (MEL) model includes P as well as N, carbon, light, and water, and is being applied to simulate succession in northern hardwood forests. Using nutrient additions of N alone in some forest stands, P alone in some forest stands, N+P in some forest stands, in replicated stands of three ages (~20, 30, and 100 years) at the Bartlett Experimental Forest in New Hampshire, the investigators will test the patterns of resource limitation. The model predicts a greater response of aboveground productivity to N+P than N or P alone. In older stands, it predicts a greater response to N than to P addition, but in younger stands, the model suggests that the supply of N from detritus should be sufficient to create P limitation.