Selective clearing and planting experiment to promote shrubland fire resilience
Spain - Experimento para aumentar la resiliencia del matorral contra incendios (Spanish)
left: Different vegetation treatments were examined on four plots in three study sites. 1)Control (no action), 2)clearing, 3)clearing and planting, and 4)planting within the shrubland. (Photo: CEAM)
right: The combination of clearing fire-prone and planting more fire resistant species is an appropriate management practice of fire-prone shrubland. (Photo: CEAM)


The combination of clearing of fire-prone seeder species and planting of more fire resistant resprouter species directs the vegetation to later successional stages which increases the resilience to fires.

The forests and shrublands in Ayora experienced a series of disturbances in the past (such as deforestation and land use), which resulted in the degradation of the vegetation and the reduction of the resilience to fires. At present, there is a high fire incidence. Post-fire landscapes regenerated with a high and continuous fuel accumulation with few native resprouter species. Therefore appropriate vegetation management is crucial. For management the major goals are to reduce the fuel load and its continuity and to increase the resilience of the vegetation to fires. Within this experiment carried out by CEAM (Centro de Estudios Ambientales del Mediterráneo, University of Valencia) different fuel management techniques were examined. They selected three study sites (Morera, Roñoso, Gachas) with a similar history of land use, vegetation composition, soil characteristics, and a typical post-fire scenario whith scarce occurrence of resprouter species. In each site, four plots were established to test the effect of the following management techniques: 1) control (no action), 2) clearing, 3) planting (within the shrubland) and 4) the combination of clearing and planting.
The main purpose of this experiment was to find out which management technique is the most appropriate to prevent fires and it was shown that the combination of selective clearing of fire-prone shrubs (fuel control) and planting of more resistant resprouter species can increase the resilience to fires and is therefore a suitable management practice. Compared to the other management techniques, there are some advantages. Clearing the vegetation (either by hand or mechanically) reduces the fire risk and enhances seedling establishment and growth. Furthermore, the cleared vegetation is chipped and applied in-situ as mulch, which protects the soil from erosion, reduces soil temperature and moisture loss, and enhances carbon conservation. Additionnally, selective clearing allows to preserve desired species and by planting resprouter species the natural processes can be accelerated. Once established, resprouter species persist for a long time which promotes an increase of the vegetation resilience. In this documentation, only the combination of clearing and planting is evaluated since this action is considered as the most appropriate management practice.
In each study site, the experimental area covered about 5000m2 (3 plots of 1000m2 each, one plot of 2000m2). To test the effect of the combination of clearing and planting, a clearing machine was used to clear a plot of 1000 m2 in all three sites. The few resprouting individuals such as Juniperus oxycedrus and Quercus ilex and also some seeder trees such as Pinus halepensis and Pinus pinaster were left standing. The planting holes (0.35 m2) were created with a tractor using a backhoe. The slash and brush chips generated by the clearing were reused in the planting holes as mulch which resulted in ecological benefits. In February 2003, native resprouters of late successional stages with a low amount of dead fuel were planted, such as Quercus ilex, Rhamnus alaternus and Pistacia lentiscus, all protected by a plastic tree shelter to prevent browsing. The seedlings were grown for 8 months in a nursery in Santa Faz (Alicante) and then transferred to a nursery in La Hunde (Ayora) one month before planting. The Regional Forest Services of Valencia provided seeds as well.
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
Technology area: 0.015 km2
Conservation measure: vegetative
Stage of intervention: prevention of land degradation, mitigation / reduction of land degradation
Origin: Developed through experiments / research, recent (<10 years ago)
Land use type:
Forests / woodlands: Natural
Forests / woodlands: Plantations, afforestations
Climate: subhumid, temperate
WOCAT database reference: T_SPA011en
Related approach:
Compiled by: Nina Lauterburg, Centre for Development and Environment (CDE)
Date: 2013-04-26
Contact person: Alejandro Valdecantos, Fundación Centro de Estudios Ambientales del Mediterráneo (CEAM), Parque Tecnológico Paterna. C/ Charles Darwin 14, 46980 Valencia, Spain. Phone: +34 609 183 599 E-Mail: a.valdecantos@ua.es

        


Classification
Land use problems:
- In Spain the prevalent dense shrublands (dominated by seeder species), which resulted from agricultural land abandonment and fire occurrence, contain a high fire risk because of both the high fuel loads and their continuity. Resprouter species have been removed in the past and are therefore scarce, whereas seeder species are abundant and increase the risk of fires. (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: Tree and shrub cover
Vegetative: Clearing of vegetation (eg fire breaks/reduced fuel)
Vegetative: Others (Introduction of fire resistant species)
Stage of interventionOriginLevel of technical knowledge
   Prevention
   Mitigation / Reduction
   Rehabilitation
   Land users initiative
   Experiments / Research: recent (<10 years ago)
   Externally introduced
   Agricultural advisor
   Land user
Main causes of land degradation:
Direct causes - Human induced: deforestation / removal of natural vegetation (incl. forest fires), other human induced causes, change of vegetation composition to fire-prone shrubland
Indirect causes: population pressure, poverty / wealth, labour availability
Main technical functions:
- control of fires
- reduction of dry material (fuel for wildfires)
- Promotion of vegetation species and varieties (more fire resistant vegetation composition)
Secondary technical functions:
- increase / maintain water stored in soil

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: medium
Topsoil organic matter: medium (1-3%)
Soil drainage/infiltration: medium
Soil water storage capacity: medium
Ground water table: 5 - 50 m
Availability of surface water: poor / none
Water quality: good drinking water
Biodiversity: medium
Tolerant of climatic extremes: seasonal rainfall decrease, heavy rainfall events (intensities and amount), wind storms / dust storms, floods, droughts / dry spells
Sensitive to climatic extremes: temperature increase, seasonal rainfall increase, temperature decrease, snow, frost

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), 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=3747Technical drawing

On the left, the situation before management is illustrated. Dense shrublands contain a high fire risk due to their high fuel amount and continuity. On the right, the situation after management is shown. The combination of selective clearing of fire-prone seeder species and planting of more fire resistant resprouter species (illustrated by tree shelters in the drawing) promotes shrubland resilience to fires. (Nina Lauterburg)

Implementation activities, inputs and costs
Establishment activitiesEstablishment inputs and costs per ha
- Cutting and chipping (in-situ) trees and shrubs (removed species: ulex parviflorus, rosmarinus officinalis, cistus albidus. Natural regenerated species which are not cleared: pinus halepensis, pinus pinaster, quercus ilex, juniperus oxycedrus)
- Planting (planted species: pistacia lentiscus, quercus ilex, rhamnus alaternus)
InputsCosts (US$)% met by land user
Equipment  
  - machine use 3089.00 0%
  - tree shelters 945.00 0%
Agricultural  
  - seedlings 4587.00 0%
TOTAL 8621.00 0.00%

Maintenance/recurrent activitiesMaintenance/recurrent inputs and costs per ha per year
- There is no maintenance, but in case of maintenance they would do selective clearings (using machines)
InputsCosts (US$)% met by land user
Equipment  
  - machine use 446.00 0%
TOTAL 446.00 0.00%

Remarks:
Slope (if the slope is steep, the work is much more difficult and takes more time), distance from a street (people can work less in a day if they have to walk far to clear/plant), vegetation density (it takes more time to clear a densely vegetated area).
The costs were calculated for the application of the technology (combination of clearing and planting) on one hectare. The costs can vary depending on the amount of vegetation which has to be cleared (site specific). The costs of the clearing amount to 1090 Euro per ha (1470 Dollar). The costs of the plantation (both labour and machines) are approximately 5300 Euro per hectare (7150 Dollar). But it should also be noted that the application of the selective clearing and planting on a vast continuous area is not the aim of this technology, but rather to apply the treatments on some selected spots to reduce the continuity of fire-prone seeder species and to increase the probability of dispersal of resprouter species (e.g. by birds). Therefore the costs would be lower than indicated here. 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 fodder production
   increased fodder quality
   increased animal production
   increased wood production
   reduced animal production
Socio-cultural benefitsSocio-cultural disadvantages
   improved cultural opportunities
   increased recreational opportunities
   improved conservation / erosion knowledge
   improved situation of disadvantaged groups
   conflict mitigation
Ecological benefitsEcological disadvantages
   reduced fire risk
   increased soil moisture
   increased plant diversity
   increased biological pest / disease control
   reduction of germination of competing seeds
   reduction of soil surface temperature
   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 loss
   reduced soil crusting / sealing
   increased animal diversity
Off-site benefitsOff-site disadvantages
   reduced risk of wildfires and damage of villages
Contribution to human well-being / livelihoods
   Not applicable since it was only an experiment, but for sure it would contribute to improve livelihoods and human well-being, forest and shrubland management could provide jobs and would also decrease the risk of fires.

Benefits /costs according to land user
Benefits compared with costsshort-term:long-term:
Establishmentslightly negativevery positive
Maintenance / recurrentvery positivevery positive
Short term returns are slightly negative because the management practice is expensive and until the trees reach a mature state, there are not many returns (in terms of wood and biomass). In the long term this management practice has very positive results because it increases the resilience to fires and can be seen as a sustainable management of fire-prone areas. Additionally, wood and biomass can be extracted. The idea is not to apply any maintenance in the first 10 years after the establishment.

Acceptance / adoption:
There is no adoption trend since this was only an experiment, but maybe there will be the possibility to upscale this technology in a regional project.

Concluding statements

Strengths and how to sustain/improveWeaknesses and how to overcome
After fires, the natural landscape regenerated with a high and continuous fuel amount and a scarce occurrence of native resprouter species. It is crucial to apply management actions to reduce the fire hazard. The experiment demonstrated that it is possible to accelerate the post-fire vegetation response (which promotes ecosystem resilience). Clearing of fire-prone species and planting of late-successional species. The management of these areas is crucial – the clearings must be repeated from time to time.
Planting of resprouting species in post-fire areas can accelerate the natural process. Clearing of the vegetation reduces the fire risk, but this treatment may also enhance seedling establishment and growth.
The slash and brush chips generated by the clearings can be reused in the planting holes. This mulch layer protects the soil surface and reduces both the soil surface temperature and the germination of competing seeds while increasing the soil moisture content, especially in the driest periods. Recurrent maintenance is crucial to ensure the effectiveness of the technology.
The combination of clearing and planting resprouting species seems to be an appropriate option for managing these areas because, once established, the resprouting species persist for a long time and lead to an increase of the ecosystem resilience. Recurrent maintenance is crucial to ensure the effectiveness of the technology.
Social and economic benefits for the locals. Especially during the economic crisis the forest management is an important source for jobs. Actually there is still a lot of management required in the forest of this region which would provide jobs in the longer term.
Almost all villagers prefer a managed forest. It has a high aesthetic and recreational value. Through the application of this technology the awareness of the risk of wildfires would probably increase. Recurrent maintenance is crucial to ensure the effectiveness of the technology. Villagers and state need to work together and ensure a long-term forest management.
Shepherds and farmers benefit from forest clearings. There are more young grasses in the forest which provides fodder for livestock. Also wild animals benefit from this food supply which in turn hinders them to destroy cultivated fields of the farmers. Recurrent maintenance is crucial to ensure the effectiveness of the Technology.
The management activities are expensive and labour-intensive. The state does not invest much money in prevention of forest fires but focuses more on fire extinction. More investment in prevention of forest fires is required and this management practice could increase the ecosystem resilience against fires in the long term in a sustainable way. This would also generate jobs. This technology implies a combination of techniques (selective clearing and planting). Costs may be reduced by implementing individual techniques but positive results may also be reduced.
The technology could result in a reduction of the animal production because grazing should be restricted after planting to ensure the growth of the planted seedlings. Since the technology would not be applied over vast areas but only locally on some plots, the fodder supply would probably still cover the needs of the animals.
Depending on the site, some soil may be exposed to erosion due to mechanical clearing. Mulching with brush chipping can minimize or even solve this problem.
After clearing, an increase in wind velocity might occur. The planted trees will grow which will again result in the reduction of this problem.


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