Forest production is strongly dependent on nutrient uptake; however, sustainable management of intensively managed plantations requires an improved understanding of this relationship when fertilization occurs frequently across short rotations. Here, we studied temporal nitrogen (N) concentration ([N]) and content (Nc) dynamics under different silvicultural practices (herbicide, fertilization, and planting density) throughout early loblolly pine (Pinus taeda) stand development (5 years). We describe relationships of [N] and Nc of different stand components (foliage, branches, stem, roots, and competing vegetation) with carbon and biomass. Our results demonstrate that [N] of perennial loblolly tissues do not respond to silvicultural practices and progressively decrease through development. While foliar [N] was most responsive to resource availability, it was not consistent across time. Controlling competing vegetation was crucial to promote the use of site resources by the crop tree and increased loblolly Nc by >500%. However, increased N uptake and expedited growth is dependent upon fertilization early in stand development. At age 5, herbicide plus reduced and full fertilization rates exhibited similar aboveground Nc, which was 32% higher than with herbicide only. Increasing planting density resulted in increased above- and belowground loblolly Nc; however, increases in Nc were not proportional with increases in planting density. Net primary productivity and N uptake were linearly related, but age/development strongly controlled N use efficiency. Our study helps to understand complex relationships between N, biomass, and silvicultural practices during early stand development and demonstrates that temporal evaluation of nutrient dynamics is crucial to better understand loblolly pine growth, carbon sequestration potential, and to inform sustainable silvicultural practices across short rotations.

森林生产在很大程度上取决于养分吸收。但是，如果在短周期内频繁施肥，对集约经营人工林的可持续管理需要对这种关系有更好的了解。在这里，我们研究了整个火炬松（种松）在不同造林实践（除草剂，施肥和种植密度）下的氮素（N）和含量（Nc）动态变化。）展位开发（5年）。我们描述了不同林分成分（树叶，树枝，茎，根和竞争性植被）的[N]和Nc与碳和生物量的关系。我们的结果表明，[N]多年生叶片组织对造林实践无反应，并通过发育逐渐减少。虽然叶面[N]对资源可用性最敏感，但跨时间不一致。控制竞争性植被对于促进农作物树种利用场地资源和使整体Nc增加> 500％至关重要。但是，氮素吸收增加和生长加快取决于林分发育早期的施肥。在5岁那年，除草剂加上减少的 和 充分的施肥率表现出相似的地上氮，比仅使用除草剂高32％。种植密度的增加导致了地上和地下的Nc的增加。但是，Nc的增加与种植密度的增加不成比例。净初级生产力和氮吸收呈线性关系，但年龄/发育强烈控制氮的利用效率。我们的研究有助于了解林分早期发育过程中氮，生物量和造林实践之间的复杂关系，并表明营养素动态变化的时间评估对于更好地了解火炬松的生长，固碳潜力以及在短轮伐期提供可持续的造林实践至关重要。