Selective forest clearing to prevent large forest fires
Spain - Clareo selectivo para la prevención de incendios (tratamientos selvícolas) (Spanish)
left: Cleared forest with chipped material applied as mulch and fresh grasses providing fodder to animals. (Photo: Nina Lauterburg)
right: The residues generated by forest clearings are chipped in-situ using brushcutters (motodesbrozadoras). The chipped material protects the soil as a mulch layer. Forest management provides jobs - many forest workers were unemployed before. (Photo: Nina Lauterburg)


Selective forest clearing aims in reducing the connectivity and the amount of (dead standing) fuel, as well as reducing the competition between regenerating pines, in order to prevent forest fires and to ensure the growth of a healthy forest.

The forests in the Ayora region experienced a huge disturbance in the past, such as deforestations, removal of key species, land abandonment, dense growth of fire-prone seeder species (high continuity of dead standing fuel), missing management, wildfires and dense afforestations. These disturbances resulted in the degradation of the vegetation, the reduction of the resilience of the ecosystem against fires and thus an increasing risk of wildfires. After fires, many landscapes regenerated with a high and continuous fuel accumulation with few native resprouter species, which made it extremely difficult to control forest fires. The dense growth not only increased the risk of wildfires but also the competition between different species (nutrients, light, space). Therefore appropriate vegetation management to increase the resilience of the ecosystem to fires and to reduce competition is crucial.
These problems are approached by selective forest clearing. The main purposes of thinning dense pine forests are the prevention of fires by reducing the fuel load and its continuity, and to improve pine regeneration by eliminating the competition between different species. As a result, the quality of the plants is improved and the amount of dead or sick plants is reduced, which is essential to ensure a healthy forest. This also leads to a higher resistance to pests which in turn again decreases the risk of fire (less dead plants). Vegetation removal produces fresh vegetation growth, therefore more diverse and nutritious fodder is provided to animals (game and livestock) in the cleared areas which is a benefit for herders. Also wild animals use this fodder supply which in turn hinders them to destroy cultivated fields of the farmers. Furthermore, honey producers make use of the enhanced growth of shrubs and the additional space created by selective clearing to place their beehives and to increase honey production. Especially during the current economic crisis forest management is an important source for jobs - most of the workers were unemployed before working in the selective clearing. Through the clearings, fuelwood is gained and offered to retired people for free for cooking and heating, allowing them to save money. Additionally, almost all villagers like to have a cleared forest due to its high aesthetic and recreational value.
In order to be selective and to preserve desired species, the clearing is done with small machines such as brushcutters and chainsaws. On average the forest is thinned until reaching a density of 800-1200 trees/ha. Species such as Juniperus, Rhamnus al., Quercus rotundifolia, Quercus faginea or Fraxinus ornus are not removed which increases the probability to have a more fire-resistant vegetation composition in future. Dead or sick plants and also a part of fire-prone shrubs such as Ulex parv. and Cistus alb. are removed. If there are both Pinus pinaster and Pinus halepensis. Pinus halepensis is cleared because they compete with each other. The roots are not removed which ensures the stability and productivity of the soil. The remaining species are pruned (“poda”) until a maximum height of 2.5m to improve the conditions of the species. Around each tree they should clear an area of 2m. After felling trees and shrubs a part of the residues is chipped in-situ and covers the soil as mulch, which results in ecological benefits (e.g. increase in soil moisture, prevention from erosion, enhancement of nutrient cycling, reduction of the soil surface temperature). If the slope is steep, it takes more time to do the clearing and it might also increase the risk of erosion afterwards. Under the best conditions (e.g. good access and terrain), 0.8ha per day are cleared (calculated for a group of 9 persons working 7 hours). In this case the costs are paid by the municipal council, which receives a part of the money from the rental fee paid by the wind mill company. The cleared areas have to be maintained depending on the speed of the vegetation growth (which amongst others depends on the soil, slope and humidity). If the clearings are done regularly, it takes less time and it is cheaper than the first clearing. It should be noted that recurrent maintenance is crucial to ensure the effectiveness of the technology.
The region of Ayora is mountainous with a dry subhumid climate (~380 mm annual rainfall). The risk of fire incidence is at its highest from June to September when there are adverse conditions like drought, high temperatures and strong winds (mainly the winds coming from central Spain, called “poniente”). The population density is very low and there are only few job opportunities (e.g. marginal agriculture, grazing, hunting, beekeeping). Most of the inhabitants work in the nuclear power plant. Forest management could be a source for jobs.
Location: Spain, Valencia
Region: Ayora/Jarafuel
Technology area: 0.5 km2
Conservation measure: vegetative
Stage of intervention: prevention of land degradation
Origin: Developed externally / introduced through project, recent (<10 years ago)
Land use type:
Forests / woodlands: Natural
Forests / woodlands: Plantations, afforestations
Climate: subhumid, temperate
WOCAT database reference: T_SPA010en
Related approach:
Compiled by: Nina Lauterburg, Centre for Development and Environment (CDE)
Date: 2013-05-11
Contact person: Vicente Colomer, Forest Agent Generalitat Valenciana (Conselleria de infraestructura, territorio y medio ambiente). Phone: +34 669 819 522 E-mail: colomer.vju@gmail.com

        


Classification
Land use problems:
- The prevalent dense shrublands (dominated by seeder species), which resulted from past agricultural land use (changes of the vegetation composition, e.g. removal of key species), land abandonment/rural depopulation and fire occurrence, contain a high fire risk because of both the high fuel loads and their continuity. Also dense forests (either afforestations or natural regeneration) show a high risk for fires. Through the modifications of the vegetation composition in the past (removal of more fire resistant resprouter species, whereas fire-prone seeder species are abundant), the resilience of the ecosystem to fires has decreased. Today a higher fire recurrence can be observed which could still be worsen by future climate change impacts, undermining more and more the ecosystem’s capacity to buffer such shocks. Furthermore, the high density of the forest results in a competition between different species which increases the amount of dead or thin material. (expert's point of view)
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Land useClimateDegradationConservation measure
Land use Land useSubhumid
Natural
Plantations, afforestations
selective felling of (semi-) natural forests, plantation forestry
subhumid
Biological degradation: detrimental effects of fires, quality and species composition /diversity decline
Vegetative: Clearing of vegetation (eg fire breaks/reduced fuel)
Stage of interventionOriginLevel of technical knowledge
   Prevention
   Mitigation / Reduction
   Rehabilitation
   Land users initiative
   Experiments / Research
   Externally introduced: recent (<10 years ago)
   Agricultural advisor
   Land user
   forest engineer
Main causes of land degradation:
Direct causes - Human induced: deforestation / removal of natural vegetation (incl. forest fires)
Indirect causes: population pressure, poverty / wealth, labour availability
Main technical functions:
- control of fires
- reduction of dry material (fuel for wildfires)
- reduction of fire-prone species
Secondary technical functions:
- increase in nutrient availability (supply, recycling,…)
- promotion of vegetation species and varieties (quality, eg palatable fodder)

Environment
Natural Environment
Average annual rainfall (mm)Altitude (m a.s.l.)    LandformSlope (%)
> 4000 mm
3000-4000 mm
2000-3000 mm
1500-2000 mm
1000-1500 mm
750-1000 mm
500-750 mm
250-500 mm
< 250 mm

> 4000   
3000-4000   
2500-3000   
2000-2500   
1500-2000   
1000-1500   
500-1000   
100-500   
<100   

    plateau / plains
    ridges
    mountain slopes
    hill slopes
    footslopes
    valley floors

flat
gentle
moderate
rolling
hilly
steep
very steep

Soil depth (cm)

0-20
20-50
50-80
80-120
>120

Soil texture: fine / heavy (clay)
Soil fertility: low
Topsoil organic matter: medium (1-3%)
Soil drainage/infiltration: medium
Soil water storage capacity: medium
Ground water table: > 50 m
Availability of surface water: poor / none
Water quality: good drinking water
Biodiversity: medium
Tolerant of climatic extremes: temperature increase, seasonal rainfall decrease, heavy rainfall events (intensities and amount), wind storms / dust storms, floods, droughts / dry spells
Sensitive to climatic extremes: seasonal rainfall increase
If sensitive, what modifications were made / are possible: The technology was not modified but it is important to add some notes to the above stated reactions to climatic extremes. The cleared areas are quite resistant against climate change or weather extremes. Only if there will be more rainfall the vegetation might grow faster and the maintenance costs could increase.

Human Environment
Forests / woodlands per household (ha)

<0.5
0.5-1
1-2
2-5
5-15
15-50
50-100
100-500
500-1,000
1,000-10,000
>10,000
Land user: employee (company, government), common / average land users, mainly men
Population density: < 10 persons/km2
Annual population growth: negative
Land ownership: state, individual, titled
Land use rights: individual, public/open access but organised (e.g. wood, hunting)
(There is some public land, controlled by the state. But there is also some private land. The access to the public land is open but organized. Permission is needed from the government to cut trees, to build a house or to hunt. There are some private hunting areas for which the hunting association has to pay a fee.)
Market orientation: mixed (subsistence and commercial)
Purpose of forest / woodland use: timber, other forest products / uses (honey, medical, etc.), recreation / tourism


blob_id=3466Technical drawing

The main purposes of thinning dense forests (some 50’000 individuals per ha) are the prevention of fires by reducing the fuel load and its continuity (both vertical and horizontal), and to improve regeneration by eliminating the competition between different species. On average the forest is thinned until reaching a density of 800-1200 trees/ha. Species such as Juniperus, Rhamnus al., Quercus rotundifolia, Quercus faginea or Fraxinus ornus are not removed which increases the probability to have a more fire-resistant vegetation composition in future. Dead or sick plants and also a part of fire-prone shrubs such as Ulex parv. and Cistus alb. are removed. The remaining species are pruned (“poda”) until a maximum height of 2.5m to improve the conditions of the species. Around each tree they should clear an area of at least 2m but ideally there should be a distance of 6m between different individuals. After felling trees and shrubs a part of the residues is chipped in-situ and covers the soil as mulch, which results in ecological benefits and provides fodder to livestock and game. (Nina Lauterburg)

Implementation activities, inputs and costs
Establishment activitiesEstablishment inputs and costs per ha
- Cutting and chipping (in-situ) of trees and shrubs (selective clearing)
- Transport of wood (fuel wood)
InputsCosts (US$)% met by land user
Labour 404.00 0%
Equipment  
  - machine use 2024.00 0%
TOTAL 2428.00 0.00%

Maintenance/recurrent activitiesMaintenance/recurrent inputs and costs per ha per year
- Cutting and chipping (in-situ) of trees and shrubs (selective clearing)
- Transport of wood (fuelwood)
InputsCosts (US$)% met by land user
Equipment  
  - machine use 446.00 0%
TOTAL 446.00 0.00%

Remarks:
The costs of selective forest clearing can be affected by numerous factors, such as slope (if the slope is steep, the work is much more difficult and takes more time), vegetation density (it takes more time to clear a dense area) and vegetation type (pine forest or shrubland), distance from a street (people can work less in a day if they have to walk far to clear). Important to note is that maintenance costs could increase with an increase in rainfall because the vegetation will grow faster.
The costs were calculated for the application of the technology (selective clearing) on one hectare. In this case, 9 people are working as a team. If the site is accessible and if the terrain is good for clearing work they can clear 0.8 ha per day. It should be noted that clearing with small machines such as brushcutters and chainsaws is much more expensive than clearing with tractors, but often it is only possible to clear with small machines (e.g. removal of trees is not possible with tractors). A tractor costs more or less 500 Euro per ha (674 Dollar per ha). A clearing of a pine forest with manual machines costs around 1800 Euro per ha (2428 Dollar per ha). The costs of the maintenance activities (e.g. second clearing) are much lower because the area was cleared already some years before. Therefore more ha per day can be cleared. In Jarafuel, a part of the costs are covered by the rental fee paid by the windmill company. The currency rate (Euro-Dollar) was calculated on November 16th, 2013.

Assessment
Impacts of the Technology
Production and socio-economic benefitsProduction and socio-economic disadvantages
   increased wood production
   increased fodder production
   increased fodder quality
   increased animal production
   reduced expenses on agricultural inputs
   increased farm income
   increased production area
   increased product diversification
   high establishment and maintenance costs
   reduced animal production
   job uncertainty
Socio-cultural benefitsSocio-cultural disadvantages
   improved cultural opportunities
   increased recreational opportunities
   improved conservation / erosion knowledge
   improved situation of disadvantaged groups
   conflict mitigation
   improved food security / self sufficiency
Ecological benefitsEcological disadvantages
   reduced fire risk
   increased soil moisture
   reduced hazard towards adverse events
   increased biological pest / disease control
   reduced evaporation
   improved soil cover
   increased biomass above ground C
   increased nutrient cycling recharge
   increased soil organic matter / below ground C
   reduced emission of carbon and greenhouse gases
   reduced soil crusting / sealing
   increased animal diversity
   reduction of soil surface temperature
   increased soil erosion locally
   increased habitat fragmentation
Off-site benefitsOff-site disadvantages
   reduced risk of wildfires
   reduced downstream flooding
   reduced downstream siltation
   reduced damage on public / private infrastructure
Contribution to human well-being / livelihoods
   Through the clearings it is easier to control fires and protect people. Furthermore it created jobs for the unemployed. In general forest management is not something people want to do, they work in this sector only if there are no other job opportunities. Forest management means a hard job and this kind of work is not well-respected in society.

Benefits /costs according to land user
Benefits compared with costsshort-term:long-term:
Establishmentvery positivevery positive
Maintenance / recurrentvery positivevery positive
Both the short-term and the long-term benefits are very positive assuming that maintenance is done. It contributes to prevent devastating fires and to guarantee a healthy forest. Together with the creation of jobs, directly after clearing there is firewood and timber available and a reduced risk of wildfires. But it should also be considered that the establishment costs are high. If maintenance is not done the long-term returns will be very negative because an increase in the risk of fire will occur again (without management, there will also be no firewood, no timber and no jobs). The maintenance costs increase the longer you wait because the vegetation will grow again densely.

Acceptance / adoption:

There is no trend towards (growing) spontaneous adoption of the technology. Clearings are only done when the state has money. Selective clearing is also applied in other countries/regions, e.g. in California.

Concluding statements

Strengths and how to sustain/improveWeaknesses and how to overcome
Through selective forest clearing the fuel amount and connectivity (vertical/horizontal) is reduced which is crucial for preventing the occurrence and spread of large forest fires. Recurrent maintenance is crucial to ensure the effectiveness of the technology. Especially the fire-prone seeder species (e.g. Ulex parviflorus, Cistus albidus) should be removed frequently. CEAM suggests to plant more fire-resistant species (late successional stages) within some spots to accelerate the natural succession and to increase the resilience of the ecosystem to fires. Green living plants have a higher humidity content which slows down a fire (oxygen is consumed). By planting late-successional species really densely you don’t allow seeders to grow. This measure could also decrease management costs and create Jobs.
There is a reduction of competition between plants which is essential to ensure a healthy forest (more nutrients, light, space). This also leads to a higher resistance against pests which in turn again decreases the fire risk (less dead or sick plants). Recurrent maintenance is crucial to ensure the effectiveness of the technology.
Fuel management through vegetation clearing presents some positive aspects with respect to other techniques, e.g. the possibility of being selective in order to preserve desired species or individuals. Furthermore, after felling trees and shrubs a part of the vegetation is chipped in-situ and covers the soil as mulch. This results in ecological benefits (e.g. increase in soil moisture, prevention from erosion, enhancement of nutrient cycling, reduction of the soil surface temperature and evaporation loss). Recurrent maintenance is crucial to ensure the effectiveness of the technology.
The trees/shrubs are cut but the roots are not removed. This ensures the stability and productivity of the soil.
Fewer fires result in a decrease of the destroyed area, less money will have to be invested in restoration or fire extinction. Furthermore, farmers, hunters and honey producers will experience fewer losses. Recurrent maintenance is crucial to ensure the effectiveness of the technology.
There are both social and economic benefits for local people. The selective clearings provide jobs for rural people, which allows them to increase their livelihood conditions. People do not depend on unemployment pays and are therefore more accepted in society. A part of the extracted wood is used for biomass, fertilizers, pellets, or firewood. Furthermore there would be improved conditions for grazing. Therefore forest management contributes to rural development. Actually there is still a lot of management required in the forest of this region which would provide jobs in the longer term. Furthermore, many local stakeholders mentioned the importance of reactivating traditional activities (such as grazing, agriculture, wood gathering) and that the villagers should get economic compensation to maintain the forest in a good state.
There are also off-site benefits. Fewer fires will result in a reduction of downstream flooding, downstream siltation and damage on neighbours’ fields. When fire removes less vegetation the soil is less vulnerable to erosion. Recurrent maintenance is crucial to ensure the effectiveness of the technology.
In Jarafuel where most of the land is public retired people receive the firewood gained by forest clearings for free. They can use the wood for cooking and heating and save a lot of money. People from the region (outside of Jarafuel) like this idea that villagers benefit from what is removed from the forest. More mechanisms like this should be developed so that people recognize that they also benefit from forest management, which in turn would ensure a sustainable forest management.
Almost all villagers like to see a cleared forest. It has a high aesthetic and recreational value (it is possible to walk through the forest). They are also aware that the risk of wildfires is reduced through this technology. Recurrent maintenance is crucial to ensure the effectiveness of the technology. Villagers and state need to work together to ensure a long-term forest management.
Shepherds, hunters and farmers benefit from forest clearings. Vegetation removal produces fresh vegetation growth, therefore more diverse and nutritious fodder is available for animals (game and livestock) in the cleared areas. Game/wildlife and livestock are better because there is an increase in fodder quantity and quality. Wild animals benefit from this food source which in turn hinders them to destroy cultivated fields of the farmers. Also honey producers benefit from the cleared areas since bees can fly better and there is more place to put the beehives, furthermore the growth of shrubs is enhanced. Recurrent maintenance is crucial to ensure the effectiveness of the technology.
The establishment and the maintenance activities are expensive and labour-intensive. Without management the technology is not effective anymore. It would be necessary to extract biomass from the forest to decrease the continuity of the trees and shrubs. In case of a lack of management the risk of fires increases. Management is crucial. Prevention measures are often less expensive than rehabilitation activities after a fire. The state should therefore invest more money in forest management and fire prevention. Managing the forest would not only decrease the risk of fire but also generate benefits (e.g. wood, biomass, fuelwood). Instead of getting unemployment pay people could get jobs in forest management. Stakeholders mentioned that it would be important to promote the forest as a sustainable economic resource and that the relation between the villagers and the forest should be enhanced. Furthermore it was mentioned that traditional activities (such as grazing, agriculture, wood gathering) should be reactivated and that the villagers should get economic compensation to maintain the forest in a good state. Especially the promotion of grazing was stressed many times. Also planting of more fire-resistant species (late successional stages) in some spots as suggested by CEAM could increase the resilience of the ecosystem and decrease management costs.
The clearing of forests has potential to prevent fires and therefore degradation. But there are also a lot of highly connected shrublands with a high fuel load which are not addressed by this management practice. Shrublands need to be cleared as well since they constitute a huge risk for wildfires.
If there is more space after clearing the first shrubs which will grow will be fire-prone early successional species, such as Cistus albidus and Ulex parviflorus. Without management, they will increase the risk of fires. Recurrent maintenance is crucial to ensure the effectiveness of the technology. Management through grazing could be a simple way to reduce the costs and the risk. By planting resprouter species really densely seeders would not grow anymore in those spots which would also decrease the fire risk and the management costs.
When the clearing is done on extremely steep slopes there might be an increase in erosion. Before clearing the soil erosion risk should be calculated.
In some areas there will be less shade which could harm some species.


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