First broadcast on 27 April 2021
In this episode, Tom Heap meets the team who've worked out how to cut trees in a way that's good for the planet.
Is logging always bad for the planet? A team from The Nature Conservancy in the United States believe they have developed a way to cut down the trees we need for construction without damaging tropical forests or adding to our carbon emissions.
Tom Heap meets Peter Ellis, the man behind Reduced Impact Logging, and his Indonesian colleagues, Purnamo and Ruslandi, who are persuading the foresters of Borneo to take up the new techniques.
Back in the UK, climate scientist, Tamsin Edwards joins Tom to crunch the numbers - how much carbon dioxide could these ideas save?
Listen now on BBC Radio 4
We asked Society Fellows Professor David Coomes from the University of Cambridge and Professor Michelle Pinard and Professor David Burslem from the University of Aberdeen, to offer some observations on the potential of Reduced Impact Logging for climate change mitigation (RIL-C) in reducing carbon emissions. Their points take some of the themes of the programme a step further.
The concept of Reduced Impact Logging (RIL) was very actively promoted in the 1990s (e.g. Putz and Pinard 1993). If successfully adopted wherever selective logging is happening in the tropics, it would significantly reduce carbon emissions. However, RIL has not been widely adopted in the past and persuading people to manage forests differently is likely to be challenging in the future too. Reduced Impact Logging for Climate Change Mitigation (RIL-C) is a novel twist, in that it seeks to persuade foresters to adopt RIL by paying for emissions reductions.
However, calculating emissions reductions from RIL is difficult; observations need to be made over a number of years to demonstrate that the damaging activities have been reduced while ensuring the same amount of timber is extracted. The complexity of the accounting process might limit uptake.
Putz et al. (2008) estimated a reduction of emissions of 0.16 gigatonnes of carbon (Gt C) per year. This estimate will change over time as the carbon density of the types of forest available for logging changes.
The method of conventional logging varies so much from place to place, meaning the benefit of applying RIL techniques will also be highly variable. In one study in Sabah, Malaysia, a PhD study at the University of Aberdeen estimated that the cumulative carbon benefit in terms of emissions reductions, higher sequestration and higher average storage, of using RIL compared to conventional logging over a 30 year logging cycle would be nearly 200 Mg of carbon per hectare. Sabah alone has 3.54 million hectares of ‘forest reserves’, the vast majority of which have been logged (in many cases several times).
Logging in Borneo, close to Crocker Range National Park (Image: Dr Alexey Yakovlev/Flickr, CC BY-SA 2.0)
In principle natural regeneration could return any forest to a pre-logging condition in terms of carbon if it’s left for long enough. RIL is faster, so it could make a contribution to the net zero by 2050 target.
RIL is particularly relevant because of the time pressures on making adjustments to achieve net zero.
Much selective logging is illegal. Even in legal concessions, there is a tendency to disobey the rules whenever it is advantageous (e.g. clearing riparian areas and steep slopes).
There is potentially a belief that current system is okay (i.e. no incentive to change).
Mining mentality (timber is so valuable, very difficult not to just liquidate).
The cost of implementing good practice often falls to a contracted operator whereas the benefits of more sustainable forestry and higher quality forest falls to forest owners.
Lack of technical expertise.
Lack of effective regulation (why do it if no one is going to force you or catch you breaking the rules).
Improving harvesting is only part of good forestry practice - the standard varies a lot across the tropics, in some places, controlling the number of trees being harvested is probably more of a priority than reducing damage because the commercial species regenerate in disturbed conditions - very different ecology to that of dipterocarp forests in Indonesia; some conservation groups are not supportive of any logging in tropical forests; in some places there are other factors that are influencing change in practice (e.g. drive towards more efficient operations, pressure for timber certification, general improvements in governance).
There is a challenge of spreading knowledge of RIL-C to remote communities and locations.
It requires additional training for forestry staff, and therefore a need to adjust curriculum for forestry training schools.
Many forestry companies have a heavy capital investment in machinery with a relatively short life-span, which incentivises short-term over-harvesting in order to service those debts - even if a lower harvesting rate would yield greater longer-term economic returns. Over-capitalisation is a significant problem for many extractive industries, not just logging.
Kuamut Forest Reserve, Sabah, Malaysian Borneo, lowland Dipterocarp forest allocated for logging during 2014 - 2018(Image: K. Yoganand/Wikimedia, CC BY-SA 4.0)
There are several co-benefits to this solution such as:
Worker safety (training operators reducing accidents) and local capacity building.
Increased timber production.
Less soil disturbance and therefore potentially reduced carbon fluxes from loss of soil organic matter. This arises because a smaller proportion of the forest landscape has been traversed by tractors and log extraction machinery. This may also result in reduction in soil erosion by logging roads and better design of skid trails, e.g. avoidance of steep slopes and riparian areas.
If the project is managed as an offset scheme involving external investors, carbon benefits could translate into economic benefits even if there is no subsequent timber harvest.
The unintended consequence would arise if more 'intact forest' was converted to forestry concessions by the subsidy.
The complexity (and associated cost) of measurement-reporting-verification procedures required to earn verified carbon credits from RIL activities could be prohibitive. It has been a major stumbling block for REDD+ projects attempting to reduce deforestation, which is much easier to monitor than compliance with the RIL regulations.
Carbon credits are awarded retrospectively, so there may be little up-front incentive to adopt the new strategy, particularly if there are capital costs.
In some forests, the tree species need soil disturbance and canopy gaps to regenerate, low impact logging doesn’t create enough disturbance to allow the species to regenerate (e.g., mahogany in Mexico, African mahoganies in Ghana).
Although meta-analyses suggest much biodiversity is conserved, there are some groups that are negatively affected.
In some places it is costly because some trees that are located on very steep slopes (or months when soils are saturated) lead to large opportunity costs associated with leaving commercial trees behind (they can’t be harvested without creating an unacceptable amount of damage) or associated with down time when operating teams cannot be working in the forest (unacceptable levels of soil damage).
It could be argued that most logging rules of timber-producing countries in the tropics already include most of the principles and criteria that are identified in western consumer countries as RIL (certainly this is true in Sabah). Therefore, an emphasis on RIL could be viewed as a distraction from the pervasive problems of lack of enforcement, corruption and illegality. Based on this, the specific logging rules are not the ultimate problem. The financial benefits from over-logging, and weak enforcement of existing policies, more than offset the low returns from carbon offsets for wise management.
Putz, F.E., Dykstra, D.P. and Heinrich, R. (2000), Why poor logging practices persist in the tropics, Conservation Biology 14(4): 951-956
Putz, F.E., Sist, P., Fredericksen, T. and Dykstra, D. (2008), Reduced-impact logging: challenges and opportunities, Forest Ecology & Management 256: 1427-1433
39 ways to save the planet is a new radio series by BBC Radio 4 developed in partnership with the Society and broadcast in 2021. It showcases 39 ideas to relieve the stress that climate change is placing on the Earth. In each 15 minute episode Tom Heap and Dr Tamsin Edwards meet the people behind a fresh and fascinating idea to cut the carbon.
Over the course of 2021, the Society will be producing events and digital content to accompany the series.
Featured card image: Peter Ellis and The Nature Conservancy
Featured banner image: Killileikko/Pixabay
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