Fine-root morphological variables are often directly correlated with soil nutrient availability and water absorption. Indirectly, these morphological variables could be related to nutrient depletion by other plants. The relationships of fine-root variables with shade, direct or indirect, are unknown. I tested the relationships between a number of soil quality variables (levels of nitrogen and lime), competition with a co-dominant tree, and shade for the range-encroaching eastern redcedar Juniperus virginiana. I measured seven fine-root parameters as indices of potential nutrient-uptake or competitive ability. I also assessed the relationships of these fine-root parameters with foraging return (i.e., tissue nitrogen, non-structural carbohydrates, relative growth rate and biomass). There were no significant (main) effects of soil amendments (added nitrogen and lime) or tree competition on any of the seven root parameters. There was a significant (indirect) effect of shade (affecting five out of seven fine-root morphological variables), and a significant interaction effect between fertilizer and lime amendments, although the last-mentioned interaction affected one fine-root variable only. There were two additional pieces of evidence that support the effect of shade: a significant difference between shaded and unshaded plants in the slope of the negative relationship between root diameter and specific root length, and a significant overall difference among all fine-root morphological variables in a principal components analysis between shaded and unshaded plants. I found that fractal dimension was the only variable for which there were positive correlations with foraging return, probably because a higher fractal dimension leads to more effective use of nutrients. I expected a negative correlation between foraging returns and fine-root characteristics that incurred substantial costs. I only found a significant cost for specific root length, which may be mediated by the unmeasured parameter of root lifespan.

细根形态变量通常与土壤养分利用率和水分吸收直接相关。这些形态学变量可能间接与其他植物的养分消耗有关。细根变量与直接或间接阴影之间的关系是未知的。我测试了许多土壤质量变量（氮和石灰的水平），与主要树种的竞争以及侵害范围的东部红杉Jun柏（Juniperus virginiana）的阴影之间的关系。。我测量了七个细根参数，作为潜在养分吸收或竞争能力的指标。我还评估了这些细根参数与觅食回报的关系（即组织氮，非结构性碳水化合物，相对生长速率和生物量）。土壤改良剂（添加氮和石灰）或树木竞争对七个根系参数中的任何一个都没有显着（主要）影响。遮荫有显着（间接）影响（影响七个细根形态变量中的五个），肥料和石灰改良剂之间存在显着的相互作用，尽管最后提到的相互作用仅影响一个细根变量。还有另外两个证据支持阴影效果：遮荫植物和非遮荫植物之间的显着差异是根直径与特定根长之间呈负相关的斜率，并且在遮荫植物和非遮荫植物之间的主成分分析中，所有细根形态变量之间的总体差异都很大。我发现分形维数是唯一与觅食回报呈正相关的变量，这可能是因为较高的分形维数可以更有效地利用养分。我预计觅食的收益与细根特征之间会产生负相关关系，从而导致大量成本。我只发现了特定根长的显着成本，这可能是由根寿命的不可测参数所介导的。在有阴影的植物和无阴影的植物之间进行主成分分析时，所有细根形态变量之间的总体差异都很大。我发现分形维数是唯一与觅食回报呈正相关的变量，这可能是因为较高的分形维数可以更有效地利用养分。我预计觅食的收益与细根特征之间会产生负相关关系，从而导致大量成本。我只发现了特定根长的显着成本，这可能是由根寿命的不可测参数所介导的。在有阴影的植物和无阴影的植物之间进行主成分分析时，所有细根形态变量之间的总体差异都很大。我发现分形维数是唯一与觅食回报呈正相关的变量，这可能是因为较高的分形维数可以更有效地利用养分。我预计觅食的收益与细根特征之间会产生负相关关系，从而导致大量成本。我只发现了特定根长的显着成本，这可能是由根寿命的不可测参数所介导的。可能是因为较高的分形维数可以更有效地利用养分。我预计觅食的收益与细根特征之间会产生负相关关系，从而导致大量成本。我只发现了特定根长的显着成本，这可能是由根寿命的不可测参数所介导的。可能是因为较高的分形维数可以更有效地利用养分。我预计觅食的收益与细根特征之间会产生负相关关系，从而导致大量成本。我只发现了特定根长的显着成本，这可能是由根寿命的不可测参数所介导的。