{'fraction_non_alphanumeric': 0.023588277340957826, 'fraction_numerical': 0.013581129378127233, 'mean_word_length': 5.481481481481482, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Root Architecture and Root:Shoot Allocation of Shrubs and Saplings in a Bruneian Heath Forest1

WATER AND NUTRIENT ACQUISITION can place conflicting demands on plants because the availability of nutrients often varies inversely to that of water. Nutrients tend to be more abundant near the soil surface than below. For example, the organic horizon accounted for more than 70 percent of total available phosphorus, a very immobile nutrient, in Amazonian dryland forests (Tiessen et al. 1994). Soil water availability typically increases with depth during rainless periods (Landsberg 1986), putting shallow-rooted species at a disadvantage. Compared to most of the deep-rooted saplings studied, a shallow-rooted species in tropical heath forest experienced the greatest reduction in leaf water potential, stomatal conductance, and net photosynthetic rate, and the highest mortality during a prolonged drought; however, it also recovered most quickly after the first rains (Cao 2000). The vertical distribution of roots is therefore expected to partly reflect trade-offs in resource acquisition—shallow roots facilitate nutrient acquisition and deep roots help to obtain water during drought. It was in this context that Becker and Castillo (1990) explained their observation of shallower rooting in shrubs compared to similar-sized saplings of canopy species. They suggested that shrubs meet the extra