Pinus patula (Patula pine or Mexican weeping pine) is native to the highlands of Mexico. However, it has been naturalised in many other parts of the world, such as Australia, Brazil, New Zealand, Argentina, Southeast Asia and Africa.
The tree first came to Africa via South Africa in 1907 before spreading to the rest of the continent.
In Kenya, it is the most important pine species, not just because of its premium products like timber, but also for its ability to remove carbon from the atmosphere.
Its local names include msindano (Kiswahili), mucinda-nugu (Kikuyu) and omobunduki (Kisii).
According to the Kenya Forest Research Institute’s (Kefri) Guide to Tree Planting in Kenya, it grows in ecological zones of between 1,600 to 3,000 metres above sea level and it is moderately drought-tolerant. The average annual rainfall in its native habitat is from 750mm to 2,000mm.
But in Kenya, it grows in zones with annual rainfall ranging from 800mm to 1,400mm.
Like the blue gum, it is fast-growing and thus uses a lot of water. Whereas it is good for soil stabilisation because of its fibrous roots, it should not be planted near water sources or with crops. Its fast growth makes it useful in climate change control.
Like its whistling pine cousin, Pinus patula produces excellent fuel wood that burns even when green and wet.
Its fibre is used in the commercial manufacture of pulp in the paper industry and boards.
The tree grows up to 30 metres tall. For pulp, it can be harvested at between 16 and 20 years and 20-30 years for timber.
Its timber is soft and is rated at a higher premium than that from the whistling pine as it sells at an average of Sh55 a foot, the same price as cypress.
When tapped, Pinus patula yields oleoresin, which is distilled to give turpentine, and rosin, which are used in paint and batik (a technique of wax-resistant dyeing applied to whole cloth) industries
The tree is one of the most important in carbon sequestration, a crucial service for regulation and mitigation of climate change through reduction of greenhouse gas emissions.
A study carried out by Forestry Research Network of Sub-Saharan Africa in Kiambu and Nyeri counties found that the tree removes high amounts of carbon from the atmosphere.
It involved 99 plots measuring 20 by 50 metres, which were established in government-managed forest plantations of selected species.
There were significant differences in the amount of carbon sequestered among species across sites.
But eucalyptus saligna had the highest amount of carbon sequestered in Nyeri South followed by Pinus patula in Nyeri North and Cupressus lusitanica in Kiambu.
The study concluded that carbon sequestered from selected tree species in central Kenya demonstrated a significant contribution towards reduction of harmful gases, specifically carbon dioxide, which is among greenhouse gases that trap heat in the atmosphere and drive climate change, causing floods, droughts and wildfires.
CarbonBrief, a climate change publication, estimates that emissions will drop by 5 per cent this year due to the economic impact of the coronavirus disease (Covid-19).
The United Nations says the world needs a drop of 7.6 per cent annually until 2030.
Pinus patula is propagated through seeds, which go for up to Sh7,000 a kilogramme at Kefri shops.
Pre-sowing treatment is not necessary, according to the Seed Handbook of Kenya (second edition; edited by Omondi, W, Maua, JO, and Gachathi, FN.) However, germination may be boosted by soaking in cold water for at least 24 hours.
The germination rate can be low. To test the viability of the seeds, put them in a container filled with water and separate those that sink from those that float. The seeds that float are generally the ones that are least likely to germinate.
The bed should be covered with mulch and kept moist. The seeds take between seven to 14 days to germinate. Transplant when a foot tall. The ideal spacing while planting is three metres.