Invasive Trees: The silent threat to fertile soil and ecosystems 

5 minutes, 57 seconds Read

Experts warn of invasive tree species that can alter soil chemistry, making it inhospitable for other plants, potentially causing harm to ecosystems, and also reducing fertility of soil.

By Chemtai Kirui

Experts are sounding the alarm on the proliferation of invasive tree species that are altering the chemistry of the soil and making it inhospitable for other plants. These invasive species have the potential to turn fertile soil barren and cause harm to ecosystems. The introduction of invasive species can have a domino effect on the local flora and fauna, disrupting the delicate balance of the ecosystem. They are urging caution in their management and control.

Women duo preparing tree seedlings, at Karura Forest. Nairobi,‎ 2022. Photo Credit: MESHA 

Risk of Biodiversity loss 

According to James Mwang’ombe, the KFS Senior assistant Director and Head of Biodiversity Management, “These invasive species can be problematic. It causes biodiversity loss. Many native plants are not adapted to coexist with exotic plants and compete for resources.” 

James Mwang’ombe, the Head of Biodiversity Management and Senior assistant Director official at Kenya Forestry service (KFS), speaking at KFS Headquarters. Nairobi, 2022. Photo credit: MESHA 

Mwang’ombe said that introducing species that is not suited for certain area is detrimental and it can turn a fertile soil barren. 

What is Invasive species? 

A report by the United Nations Environment Program (UNEP), defines Invasive species as, ‘Species that grow and reproduce quickly, and spread aggressively, with potential to cause harm.’   

The report indicates that ‘Invasive Alien Species, which can be plants, animals or pathogens, are introduced species (intentionally or unintentionally) that become established in a new environment, then spread in ways that are destructive to human interests and natural systems.’ 

Mwang’ombe, who was speaking at the KFS Headquarters, in Nairobi, during a media science café organized by Media for Environment, Science, Health and Agriculture (MESHA), said that “One should investigate the risks of transplanting a tree from one region to another, before deciding on exotic tree planting.” 

A plantsman watering tree seedlings bed at the Karura forest. Nairobi, 2022. Photo Credit: MESHA 

What is the suitable approach? 

KFS officials say that Kenya has a potential of setting up a good base for economic growth and ecological stability if communities adopt correct tree planting exercise.  

“Kenya Forestry Service policy calls for a 10 % tree cover in farmlands which equates to about 74 trees per acre.” said Beatrice Mbula, the Deputy Chief Conservator of Forests (Advisory and Chief Liaison) 

Kenya Forestry Service Officials and Journalists associates of Media for Environment, Science, Health and Agriculture (MESHA) listening in, during a presentation by Betrice Mbula, the Deputy Chief Conservator of Forests, at the KFS Headquarters. Nairobi, 2022. Photo credit: MESHA 

“The biggest chunk of afforestation needs to happen in our farms and in community forests.” said Mbula. 

Community involvement in Forestry Management 

“Through associations such as Participatory Forest management Plans, Community forests associations (CFAs) and Plantation establishment and livelihood improvement scheme (PELIS), we ensure community interest are catered for while enlisting their support for forest management.” said Mbula. 

KFS manages two million hectares of Forest cover in the country out of which, 150,000 hectares is under Plantation scheme. 

“CFAs are the registered community members who work under PELIS, to grow food crops that do not compete with trees,” said Mercelyne Khalumba, Plantation Division official at KFS. 

Mercelyne Khalumba, Plantation Division official at KFS explaining how the plantation establishment and livelihood improvement scheme works at the MESHA organized Media café in KFS Headquarters. Nairobi, 2022. Photo credit: MESHA 

She said that KFS has temporarily stopped Maize farming in these plantations pending findings from ongoing research to decide whether a crop that grows taller than a tree seedling is conducive for its growth. 

“Plantation scheme generates good economic return for farmers. A hectare of land brings about three hundred thousand shillings, annually,” said  Khalumba. 

While addressing the controversy that surrounds community using forest land for farming, Eric Nahama, the Partnerships and Outreach officer at KFS said that “These lands are meant for harvesting — When I plant Cyprus tree in plantation, I know that after 30 years, I will harvest.” 

“If you harvest trees within that confinement of the stipulated land, then the question of decreasing or destruction of forest cover does not arise.” said Nahama. 

Eric Nahama, the Partnerships and Outreach official at KFS, speaking on the importance of Commercialization of forestry and how it works without destroying forest cover, at KFS headquarters in Karura Forest. Nairobi, 2022. Photo Credit: MESHA 

Tree cover plays a crucial role in building up landscape resilience to climate change effects.  

“Trees hold on to moisture captured from mist, which ends up on the soil, helping in ecosystem service improvement.” said Mwang’ombe.  

Money grows on trees 

With Kenya heading towards commercialization of forestry, officials say, it will be wise to adapt tree-planting. The type of tree being planted decides the value one will incur. 

Dr. Monica Nderitu, the regional environment, and Climate Change advisor at Vi agroforestry, says that farmers can reap many benefits from tree planting, “Fruit trees, can be a source of food security, nutritional and economical value. It can be good for pollinators, making room for bee keeping and honey harvesting, and certain species like Calliandra, can be used as fodder for livestock.” 

Dr. Monica Nderitu, the regional environment and Climate advisor, at Vi Agroforestry, poses for a photo at the Vi Agroforestry Headquarters in Nairobi, 2022. Photo Credit: Chemtai Kirui 

Not all trees are Agroforestry trees 

“Eucalyptus, is an investment tree” says Mbula. “This species is fast growing. One can harvest — shatters, poles, and timber products, within a brief period.” 

DCCF. Beatrice Mbula speaking on the Innovative approaches to sustainable forest management in Kenya, at KFS Headquarters. Nairobi, 2022. Photo Credit: MESHA 

“However, Eucalyptus should not be planted in a water-catchment area, because it takes up a lot of water — the leaves are poisonous to the soil, meaning no other crop can grow in its ground.” she said, adding that “A farmer should consider zoning their land and finding a location that is not environmentally sensitive, to plant such species as Eucalyptus.” 

What to do 

A figure of 300 tree planting per head has been raised, to enable Kenya rise its Forest cover to 20% come 2030, a growth encouraged globally, to limit the average global temperature increase to 1.5°C. 

A sectional view of tree seed bed at Karura forest. Nairobi, 2022. Photo credit: MESHA 

Delegates at the 27th meeting of United Nations Climate Change conference have launched ‘The Forest and Climate Leaders’ Partnership (FCLP), which aims to unite action by governments, businesses and community leaders.’ FCLP seeks to halt forest loss and land degradation by 2030. 

For beneficial tree farming, Mwang’ombe says “Lets avoid aimless transplantation. Invasive species can cause economic loss, land degradation and biodiversity loss.” 

Planting appropriate tree species can enhance biodiversity, reduce carbon footprint, improve air, water quality, and mitigate climate change.

Similar Posts