Global‐scale patterns of nutrient density and partitioning in forests in relation to climate

Abstract

Knowledge of nutrient storage and partitioning in forests is imperative for ecosystem models and ecological theory. Whether the nutrients (N, P, K, Ca, and Mg) stored in forest biomass and their partitioning patterns vary systematically across climatic gradients remains unknown. Here, we explored the global-scale patterns of nutrient density and partitioning using a newly compiled dataset including 372 forest stands. We found that temperature and precipitation were key factors driving the nutrients stored in living biomass of forests at global scale. The N, K, and Mg stored in living biomass tended to be greater in increasingly warm climates. The mean biomass N density was 577.0, 530.4, 513.2, and 336.7 kg/ha for tropical, subtropical, temperate, and boreal forests, respectively. Around 76% of the variation in biomass N density could be accounted by the empirical model combining biomass density, phylogeny (i.e., angiosperm, gymnosperm), and the interaction of mean annual temperature and precipitation. Climate, stand age, and biomass density significantly affected nutrients partitioning at forest community level. The fractional distribution of nutrients to roots decreased significantly with temperature, suggesting that forests in cold climates allocate greater nutrients to roots. Gymnosperm forests tended to allocate more nutrients to leaves as compared with angiosperm forests, whereas the angiosperm forests distributed more nutrients in stems. The nutrient-based Root:Shoot ratios (R:S), averaged 0.30 for R:S N , 0.36 for R:S P , 0.32 for R:S K , 0.27 for R:S Ca , and 0.35 for R:S Mg , respectively. The scaling exponents of the relationships describing root nutrients as a function of shoot nutrients were more than 1.0, suggesting that as nutrient allocated to shoot increases, nutrient allocated to roots increases faster than linearly with nutrient in shoot. Soil type significantly affected the total N, P, K, Ca, and Mg stored in living biomass of forests, and the Acrisols group displayed the lowest P, K, Ca, and Mg.

Global Data Analysis Shows That Soil Nutrient Levels Dominate Foliar Nutrient Resorption Efficiency in Herbaceous Species

“…This supposition is consistent with most of previous studies ( Aerts, 1996 ; Aerts and Chapin, 1999 ; Yuan and Chen, 2015 ). However, we should note that total soil nutrient level may not be indicative of soil nutrient availability though it has been widely used in many ecological studies ( Rejmánková, 2005 ; Zhang et al, 2018 ). Factors such as soil pH, humus, and mineralization may also influence soil nutrient cycling and bioavailability, leading to the un-relatedness between these two variables ( Barber, 1984 ; Vitousek, 1984 ; Yuan et al, 2006 ).…”

“…Total N and P density were used in this study rather than plant-available forms because it is almost impossible to acquire soil N and P availability data which were missing in the vast majority of literatures we collected. Additionally, total soil nutrient content should be at least partially correlated with soil available nutrient status ( Bridgham et al, 1995 ) and has been used widely in large scale ecological studies ( Rejmánková, 2005 ; Zhang et al, 2018 ).…”

Deciphering Genetic Architecture of Adventitious Root and Related Shoot Traits in Populus Using QTL Mapping and RNA-Seq Data

“…Root absorbs water and nutrients to offer growth substances for carbon fixation process in shoot leaves, while shoots provide mechanical support and transfer pathway for organic substances [2]. The biomass partitioning patterns between root and shoot are related to plant growth rate, life habitats, nutrient density, and environmental adaptability [3][4][5]. Vegetative propagation is an important reproductive pattern in many woody species, and adventitious root formation is a limiting step in vegetative propagation [6].…”

Biomass:N:K:Ca:Mg:P ratios in forest stands world‐wide: Biogeographical variations and environmental controls

“…The N and P can be reabsorbed from stem wood before it dies and becomes heartwood (Vitousek, 1982). Thus, as a whole, the quantity of dry biomass stored per gram of N and P was greater in older forests owing to the increasing proportion of wood with stand age (Tables 1 and 4; Zhang, Song, et al, 2018), indicating a dilution effect with age owing the increase of non-nutrient-rich organs.…”