Botanic Gardens Conservation International
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Approaches to tree conservation

Volume 12 Number 2 - July 2015

Emily Beech and Joachim Gratzfeld

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Introduction

Just as there are many tree species, there are many approaches to their conservation. Trees occur in different habitats and ecosystems and are at risk due to a diverse range of threats including land use changes, overexploitation and climate change. These threats result in different consequences on the ground; the habitat may have disappeared, been replaced or become degraded. Some tree species have declined to the point at which they are in need of special help in order to survive.
Covering an area of 9,596,961 km², China features a large diversity of ecosystems with numerous rare and threatened native trees. BGCI’s projects operate in a range of these habitats, including tropical rainforests, temperate desert, riparian forest as well as temperate and subtropical forests. The threats to trees differ in each location, requiring multiple approaches to their conservation.
Here we take a quick look at the varied ways in which local Chinese partners and BGCI are working together to conserve the threatened trees of China.

Species recovery

The focus of the Global Trees Campaign is to protect and improve the conservation status of
threatened trees.  There are 9,641 threatened trees worldwide and China is home to at least 760 of these species. Assisted species recovery focuses on one or several species with few individuals remaining in the wild and gives a helping hand to increase numbers and encourage natural reproduction in the future.

Target 8 of the Global Strategy for Plant Conservation (GSPC) calls for 75% of threatened species to be in ex situ collections by 2020. In order for collections to have the greatest value to conservation and reintroduction programmes they must represent the genetic variation of the species.
However, many threatened tree species are not well represented in ex situ collections. It is therefore necessary to improve this representation and develop propagation protocols to enable population reinforcement in situ.

In the case of Magnolia sinostellata, it is its horticultural value which has directly contributed to its decline. Only three populations are known to remain in the wild with limited genetic diversity. BGCI, in collaboration with Fairy Lake Botanical Garden, Shenzhen has been working to improve the conservation status of this species in Zhejiang. Ex situ conservation collections are being established to represent all three remaining populations along with the development of propagation protocols, using cuttings, grafting and dividing. Efforts to enrich the dwindling genetic diversity of Magnolia sinostellata are a particular focus in one population (Jingning population) which has the least fertile seeds. This project is in its early stages and it is hoped that work will ultimately lead to population reinforcement and reintroduction programmes in the future. There are plans to plant out 1,000 – 2,000 seedlings in to the wild, to improve the chances of self-reproduction and population growth.
Other BGCI species recovery programmes are in their later stages and show promising results. A project in collaboration with Guilin Botanical Garden, the Guangxi Institute of Botany and the Chinese Academy of Sciences (CAS) aims to improve the conservation status of three rare Golden camellias, Camellia nitidissima, C. euphlebia and C. tunghinensis. The project has so far successfully propagated all three species and has introduced 6,000 plants into a demonstration base, with an additional 20,000 plants being grown in three nurseries in the vicinity. Ex situ collections in Guilin Botanic Garden and Nanning Arboretum are now extensive, harbouring the genetic diversity of the wild populations.

Major efforts to maximise the genetic diversity of botanic garden ex situ collections are also being developed at Xishuangbanna Tropical Botanical Garden.

Ecosystem restoration

It is not only individual species that are in in danger. Many unique ecosystems are rapidly becoming degraded or damaged to the point where they no longer provide the ecosystem services they once offered. Restoration of an ecosystem involves facilitating natural succession. Human disturbances often prevent this process and interventions are needed to kick-start this process, for instance by removing exotic plants, reducing soil erosion and reintroducing native species.

In partnership with Xishuangbanna Tropical Botanical Garden (XTBG), BGCI is working to restore tropical forest remnants in Xishuangbanna, Yunnan. The tropical forest of the region is fragmented due to the increase in cash crop cultivation, especially large-scale rubber plantations. One of the remaining, yet degraded forest areas is Dai Holy Hill Forest. Large, mature native trees have been extensively extracted for timber, leaving the forest floor liable to erosion.  With the aid of historical records and ex situ collections, this collaborative project aims to restore the forest remnant to a similar plant composition as was present prior to disturbance. Two years into this project, several hundred saplings of 25 endemic woody species have been planted in a ten-hectare pilot restoration site in the forest. Exotic weeds have been removed with the help of the local community. In the long term, this project hopes to scale up planting as well as encourage similar activities in other forest remnants.
Another example of BGCI’s efforts to restore ecosystems and unique habitats in partnership with our members is the conservation work carried out in riparian forests along the Tarim River in the arid Xinjiang region. The poplar forests are under a triple threat from expanding agriculture, livestock grazing and a shrinking water table. In partnership with Tarim University, BGCI is working to protect the habitat whilst propagating and planting two of the target tree species, Populus euphratica and P. pruinosa in pilot plots. Seed regeneration is low so studies are ongoing to identify natural ways to promote natural reproduction. In the meantime, planting of vegetatively propagated individuals is being carried out.

Boosting conservation through livelihoods enhancement and community engagement

2010 figures from the World Bank estimate that 84.1 million people in China live on less than $1.25 a day. Poverty pushes communities towards unsustainable levels of harvesting, encouraging conversion of forest to agriculture and the over-exploitation of timber resources for income generation.
Conservation programmes will therefore be most successful when they consider the needs of local communities. In certain locations, communities have been exploiting forest resources without knowledge of the full impact on tree populations. A key to reducing the threats to many of these species is to provide incentives and training to avoid future unsustainable harvesting.

For instance, much of the natural forest surrounding Dahetou village in southern Yunnan is owned by the community and individual households. Threats come in the form of various forms of commercial interest, especially the extraction of timber.  Working with the Yunnan Institute of Environmental Science, BGCI is promoting population reinforcement programmes of two rare flagship trees, Magnolia cathcartii and M. doltsopa, which are heavily utilised in local construction. There is a real need for reliable incomes in the village to prevent further overharvesting of forest resources for economic reasons. In addition to propagating and planting hundreds of saplings of the two species, public outreach materials with information on the ethnobotanical importance of local plant diversity have been produced and distributed to the local community. In future the project will facilitate income generation through enhanced promotion of home gardening of medicinal species to reduce overreliance on the forest natural resources.

Although widely acknowledged, the importance of engaging local communities from the outset of a new conservation endeavour is still often overlooked. When ecosystems and specific tree species are faced with human threats, it is essential to identify the reasons why people resort to unsustainable exploitation. Without tackling the drivers of decline of a tree species it is likely to face further problems in the future. Projects which directly affect local communities can be viewed more positively if they incorporate elements of community engagement, opportunities for employment and education programmes.

Most of BGCI’s tree conservation projects therefore include specific social aims, working in harmony and with the help of the local community to ensure that people directly experience the benefits of conserving trees and their habitats. For example, the Golden Camellia project in Guangxi mentioned above, aims to enhance the incomes of local farmers by providing access to high-value plant resources, while work in Yunnan has directly engaged several hundred school children in the restoration of tropical forest remnants in Xishuangbanna.

One of the most successful examples of this approach was a restoration project run between 2008 and 2011 in Pingbian county, Yunnan to conserve three globally threatened trees, Dipteronia dyeriana, Magnolia odoratissima and Magnolia aromatica. During the project, stakeholder workshops were held to raise awareness in the local community of the importance of plant conservation. Encouraged by these sessions, several farmers set up nurseries for threatened tree species, in addition to partnering on the establishment of a ‘near situ’ conservation field collection with over 14,200 saplings of threatened species. This generated additional income opportunities from the sale of seedlings.

Education

Target 14 of GSPC calls for plant conservation to form part of education and public awareness programmes.

BGCI’s project in the Zhibenshan Mountains in west Yunnan practises extensive replanting of threatened species in an area degraded from mining activities and extraction of natural resources by local communities. Alongside this, the project has also developed numerous outreach activities to engage local people in the conservation work, linked with the establishment of a series of interpretation materials such as panels along the side of a new road in the project area to promote interest and pride in the surrounding plant diversity and the importance of securing it for the future.

Conclusion

As discussed above, the threats to native tree species are not homogenous across a country like China, with a large range of habitats and social settings. Before embarking on a tree conservation project, there are numerous issues to consider and stakeholders to consult.  These include conservation status assessments to identify threatened species of the area, historical records and floras to assess the differences in diversity and the amount of damage which has occurred, the drivers for the threats, as well as uses of plant resources by the local community. All of these factors will influence which approach or combination of different methods would be most successful in conserving the area’s target trees and restoring the habitat at large.

The success of former and continuing projects of BGCI and partners in China demonstrates that tree conservation can have benefits which go far beyond the immediate protection of the target species. This work also endeavours to inspire the next generation of ‘environmental stewards’ and boost ownership of and pride in the local biodiversity. The projects listed above represent only a snapshot of BGCI’s work in China. More information about BGCI’s China programme can be found on the BGC website (www.bgci.org), with information also available in Chinese (www.bgci.org/china).