Researchers trace large-scale understory biomass across China’s forests

BEIJING, Feb. 14 (Xinhua) — Chinese researchers have traced understory biomass and its allocation across China’s forests, according to a research article recently published in the journal Science of the Total Environment.

Understory vegetation, generally consisting of the understory shrub layer, herbaceous layer and ground cover moss layer, is a significant component of any forest ecosystem and plays a vital role in biodiversity maintenance and the ecosystem’s carbon cycle.

Deciduous birch forest with fren understory, China.

Biomass is commonly used to quantify the productivity of forest ecosystems. Biomass allocation also reflects the adaptability of plants to different environments. It is generally expressed by the ratio of underground and aboveground biomass of plants or the root-shoot ratio (R/S Ratio).

The researchers from the Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, cooperated with Chinese and American institutions and compiled a large database of understory biomass at the community level across China’s forests to explore the large-scale patterns of understory biomass and root-shoot ratio.

They found that the understory biomass and root-shoot ratio varied largely with forest types, and decreased with increasing longitude, but increased with elevation.

Understory vegetation in rainforest, Xishuangbanna, Yunnan Province, China.

Mean annual precipitation was the most important driver in determining root-shoot ratio, the research article reported.

The study sheds new light on the mechanisms underlying the variations in understory biomass and its allocation over a broad geographic scale.

The researchers believed that their findings will improve predictions of understory community dynamics in response to climate change and aid in further optimizing ecosystem process models.

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Science of The Total Environment

Abstract

Plant biomass storage and its allocation reflect the ecosystem productivity and adaptation to different environments. 

Understory vegetation is a significant component of any forest ecosystem and plays a vital role in biodiversity maintenance and the ecosystem’s carbon cycle.

Although many studies have addressed the relationships of climate, stand structure and resource availability with understory biomass and its allocation at local scales, the large-scale variation of understory biomass and allocation and their underlying mechanisms remain unclear.

This research compiled a large database of understory biomass at the community level across China’s forests to explore the large-scale patterns of understory biomass and R/S ratio, and to quantify the relative importance of drivers.

Understory biomass and R/S ratio varied largely with forest types, and decreased with increasing longitude, but increased with elevation. Understory biomass increased with increasing latitude, mean annual temperature (MAT), and mean annual precipitation (MAP), while the R/S ratio decreased with latitude, MAT, and MAP. Stand structure had a strong effect on the variations in understory biomass. MAP was the most important driver in determining R/S ratio. This synthesis provides a first assessment of the large-scale patterns of understory biomass and allocation and sheds new light on the mechanisms underlying the variations in understory biomass and its allocation over a broad geographic scale.

These findings will improve predictions of understory community dynamics in response to climate change and aid in further optimizing ecosystem process models.

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Sources:

Xinhua, 14 Feb 2022. http://www.china.org.cn/china/2022-02/15/content_78048953.htm

Chinese Academy of SciencesXishuangbanna Tropical Botanical Garden,
‘Large-scale patterns of understory biomass and its allocation across China’s forests’, Jan 2022. http://sourcedb.xtbg.cas.cn/yw/ywlw/202201/t20220118_6345213.html

Science of the Total Environment, vol. 804, p. 150169, Yanqiang Jin  et al, ‘Large-scale patterns of understory biomass and its allocation across China’s forests’, January 2022. https://doi.org/10.1016/j.scitotenv.2021.150169