To enable implementation of plantations according to the FAO principles (Box 8.1), in particular in relation to effective, transparent and integrated land-use planning, the costs and benefits and synergies and trade-offs of the many different options that may be available must be known or assessable. Therefore agreed valuation systems for ecosystem goods and services are required (see Chapter 2). Financial valuations often disregard the importance of social and cultural values, although the latter are important and should still have a place in decision-making (see principle 4 in Box 8.1). In economic terms, all goods and services can be defined as use values and non-use values. Socio-cultural values are usually lower in plantations than in natural forests and the ecological values of plantation forests depend largely upon the condition of the landscape replaced by the plantation. Although valuation systems, as discussed in Chapter 2, have a number of shortcomings, they can help to highlight the synergies, trade-offs and implications of different design and management options for plantations.
There is no form of plantation management, or any other form of natural resource management for that matter, that can provide a maximum of all ecosystems goods and services to all stakeholder groups. Some of the services conflict with each other and it would not be possible to try to maximize wood production, carbon sequestration, conservation of biodiversity, and social and cultural benefits in the same plantation stand (Figure 8.1). However, as formulated in the last of the FAO principles for responsible management of planted forests, new approaches would seek a balance of economic, environmental and social objectives at higher spatial scales. With increasing spatial scale, that is moving from one plantation stand or one property to the watershed or landscape, it becomes increasingly easier to reconcile conflicting or non-complementary objectives of management. In addition, in any landscape setting there will be a range of different interest priorities with regard to natural resource management represented by different stakeholder groups or sections of society (Brown, 2005). Satisfying these interests in different parts of the landscape may reduce conflict. Also, many of the ecosystem services depend on ecosystem processes that operate at different spatial and temporal scales, many of which exceed the scale of traditional management (Christensen et al, 1996), such as plantation stand or block and rotations. To appropriately consider these spatial and temporal dimensions, models are required that permit the analysis of spatial and temporal interactions of different types of land use on the provision of ecosystem services in the landscape. The actual planning of plantations in the landscape would be best based on a decision support framework including steps such as environmental and social impact assessments that draw on this information about cost and benefits as well as trade-offs and synergies associated with the different options. An example for such a decision support framework can be found in Kanowski and Murray (2008).
There are several studies dealing with tools to assess the effect of silvicultural techniques on the maintenance and provision of forest goods and services. For example, Kochli and Brang (2005) modelled the effect of different forest management scenarios on recreational suitability and water- and air-purification potential. They show how such an approach may help to explain how different goods and services are interrelated, and what the trade-offs are of the various stand types. Other studies show that the inclusion of high conservation value areas and biodiversity corridors could help to improve
Increasing balance Spatial Scale between objectives for provision of ecosystem services
Region Landscape Catchment Mgmt block Plantation stand
increasing conflict between objectives foe provision of ecosystem services
Figure 8.1 With decreasing scale of management, the conflict between the provision of different ecosystem services or forest values increases. Sustainable solutions aiming at the balanced provision of ecosystem goods and services can only be achieved at higher spatial scales of management
Source: adapted from Bauhus, 1999
biodiversity levels in plantation areas without affecting the production function (e.g. Barlow et al, 2007; Cyranoski, 2007).
Table 8.1 is an attempt to illustrate these trade-offs between a range of ecosystem goods and services related to the management options at the spatial scale of plantation stands and landscapes. Here, the management encompasses different silvicultural options, which have already been mentioned in Chapter 5, and landscape-level planning options. In the following, some examples from this table, which reflects the information provided in previous chapters, will be explained.
As can be seen from Table 8.1, most of the measures that benefit biodiversity, impact negatively on plantation productivity, both at the stand as well as the landscape level. However, at the landscape level, it would be important to separate between effects that impact on the production per unit of planted land or on the overall plantation estate including other forms of vegetation or land-use types. For example, maintaining corridors of native vegetation instead of converting them to plantation stands, may reduce productivity at the estate or property level, but there is no likely negative influence on the productivity of the plantation stands. Perhaps these are on average even more productive and more efficient to manage, if the native vegetation is occupying parts of the landscape that are less fertile or difficult to cultivate, such as wet soils, steep slopes or rocky outcrops. The synergies
Table 8.1 Estimated trade-offs between the effects of certain management options on selected ecosystem goods and services including the provision of biodiversity, carbon sequestration or storage, clean water in sufficient quantity, and provision of non-wood forest products
Plantation Biodiversity Carbon* Water* Amenity productivity values
Structural retention Use of native species Mixed-species stands Long rotations Thinning Site preparation Herbicides and fertilizer Landscape level
Riparian buffers (of native vegetation) Retaining patches of native vegetation Connectivity between plantations and native forests
Maintaining landscape heterogeneity (different land-use types, special places, etc.)
# Regarding the influence of plantations to reduce atmospheric CO2, sequestration and storage need to be separated. Sequestration, the uptake of carbon into vegetation and its partial transfer into the soil pool, removes CO2 from the atmosphere. This process is tightly coupled with plantation productivity. Storage of C in vegetation and soils simply prevents C from being released to the atmosphere as CO2. Forest systems such as plantations may have a high sequestration potential but little storage, whereas the opposite situation can be found in old-growth forests. For many of the management options it is difficult to ascertain the effect that they have on atmospheric CO2 since this depends to a large extent on the fate of the material harvested (see Chapter 3). If the harvested wood is turned into long-lived products, which, at the end of their service live, are used energetically to offset fossil fuel burning, the effect can be very positive. In contrast, if the wood is turned into short-lived products (such as paper), and is not subsequently used as an energy source, the overall effect may be less than if the wood was left in the forest to decay (Profft et al, 2009). Therefore, the ultimate effect of plantations on C cycling and atmospheric CO2 cannot be assessed within the plantation management system.
* For the purpose of this assessment, management options were considered to have a positive effect on water services, if they contribute to cleaner water and more groundwater recharge from the land (but see discussion on salinity, Chapter 4). The effect is considered negative, if planning or management options lead to water pollution and reduced groundwater recharge from the land carrying plantations.
Note: + = positive effects, - = negative effects, 0 = neutral effect, ? = unknown or uncertain effects, brackets indicate that the effect may not be so clearly positive or negative depending on other factors not captured here and trade-offs between biodiversity and productivity at the landscape level depend largely on the forest policy context. If plantation establishment is directly related to and dependent on the area of native forests set aside for conservation, there can be strong synergistic effects (Paquette and Messier, 2010). In addition, there are also options to increase biodiversity values that have little or no additional costs (see Chapter 5).
Most measures that are suited to improving biodiversity in plantation landscapes also have positive effects on amenity values. Owing to their orderliness and their uniformity in shape, structure and composition, plantations can have a dramatic impact on amenity and recreational values (Evans, 2009). Artificial boundaries, strong contrasts and sharp edges between stands and large clear-felled areas or other land-use types and the monotony of landscapes dominated by single species are important aspects of how the public perceives planted forests, although perception may also be influenced by the designation of the forested landscape (Anderson, 1981) and the history of afforestation and forest use (Ní Dhubháin et al, 2009). However, the preservation of patches of native vegetation and the maintenance of landscape heterogeneity as well as the creation of stand structural diversity, are likely to benefit the cultural services of planted forests.
In general, there are mostly synergies between the supporting ecosystem services such as the maintenance of soil resources, water and nutrient cycles, and biodiversity. However, most of the above-listed management options that have a direct or indirect negative effect on plantation productivity, have a positive influence on water services and vice versa (e.g. Vertessy et al, 1996; Jackson et al, 2005). However, this does not apply universally to all other -including undesirable and unintended - negative effects on productivity, as for example through soil compaction or erosion. Here, the focus is on effects on the physiological activity and transpirational demand of planted forests. Where measures such as structural retention or longer rotations result in fewer young and vigorously transpiring trees on site, the water demand of plantations will also decline. Less productive native species are likely to consume less water, than more productive exotics such as eucalypts, which have been criticized for their high water demand (Calder, 2002). Long rotations are likely to reduce the average plantation productivity, if the rotations are extended substantially beyond the culmination of mean annual increment. Slower-growing, older plantations will have a lower transpirational demand (Vertessy et al, 1996) and less frequent disturbances will also lead to overall improved water quality (Croke et al, 2001). Reduced transpiration and interception following thinning will increase water yield from plantations (e.g. Breda et al, 1995), albeit only for a limited period of time (e.g. Lane and Mackay, 2001), while thinning is unlikely to have negative impacts on water quality, except through the use of forest roads and extraction tracks. In contrast, typical plantation management practices such as site preparation and the use of herbicides and fertilizer have the potential to reduce water quality through the disturbance of soil, removal of protective soil cover and addition of nutrients, which may not be taken up by the vegetation (e.g. Malmer, 1996). However, these effects can be minimized through adherence to appropriate codes of forest practice.
Options to improve water services from plantations at the landscape scale are largely related to the percentage area under plantation, the specific location of plantations and the protection of soils and waterways (see Chapter 4). Here, the services can be optimized through policy settings, certification requirements or sound landscape planning (see Chapter 7). However, stand-and landscape-level management options to improve water services of plantations are unlikely to conflict with the provision of other ecosystem goods and services besides the production function (e.g. Wang et al, 2009).
Synergies and trade-offs with other ecosystem goods and services are most difficult to identify for the carbon sequestration or storage function of plantations, because the influence of the above-considered management options depends on many other factors, such as the fate of the harvested wood. However, most options that increase productivity at the stand level, are likely to also increase the sequestration of carbon, unless these increases are at the expense of soil stored C, which may be the case for site preparation. While the effects of site preparation on C storage are likely to be negative in the short term, in particular in relation to soil C (Paul et al, 2002), increased productivity in the long term may offset these reductions. While C sequestration may be reduced through longer rotations owing to reduced productivity, it is likely that more C is stored on site.
At the landscape scale, interspersing plantations with buffer strips and reserves of native vegetation creates patches with more long-term C storage than in the plantation stands, although the C sequestration in these patches may be less than in the highly productive plantations. Table 8.1 illustrates that focusing plantation management on mitigating climate change through C sequestration and possibly replacing fossil fuels through bioenergy, may have serious implications on many other ecosystem services, in particular if perverse incentives are provided for some short-term goals (e.g. Danielsen et al, 2008).
At the stand scale, the production of wood and fibre has limited synergies with the other ecosystem services listed here, except for C sequestration. Typical measures to increase plantation productivity such as site preparation and the use of fertilizers and pesticides have no direct beneficial effects on the other ecosystems services. However, Table 8.1 provides a very general and simple perspective on trade-offs and conflicts between services, which are often specific to the site and context. The concept shows that it is necessary to identify how different ecosystem goods and services may be differently affected to optimize their provision at various scales. The table also shows that synergies are easier to achieve and trade-offs easier to avoid at the landscape scale when compared to the stand scale. However, higher provision of other ecosystem services often comes at the expense of plantation productivity. Therefore one of the important challenges is to devise mechanisms to reward landowners for these other plantation functions that may conflict with the production of conventional plantation products. However, only in very few cases have ecosystem goods and services been quantified for a particular plantation setting (e.g. Nambiar and Ferguson, 2005; Barlow et al, 2007). And few studies have aimed to explore what the optimal spatial aggregation of the various stand types should be to deliver the best mix of goods and services. To achieve this, several studies suggest a combination of forest growth models, geographic information systems (GIS) and indices of goods and services to support the development of land-use visions and forest planning policies on a regional scale (e.g. Kochli and Brang, 2005).
So far many challenges remain with incorporating and applying the ecosystem goods and services approach in actual design, planning and management at the landscape level (de Groot et al, in press). Only a few ad hoc attempts have been made to use spatial planning as a tool to improve the overall yield of ecosystem goods and services and to find the appropriate level of trade-offs and synergies at the landscape level. For instance Van Eupen et al (2007) used scenario-dependent maps, which indicate habitat suitability of landscapes for certain flagship species. When integrated with planning for the other most important provisioning, regulating, cultural and supporting goods and services, this could be used in new approaches for plantation planning, for example in the restoration of degraded forest landscapes in tropical areas to address both sustainable use of biodiversity as well as the alleviation of rural poverty (e.g. Lamb et al, 2005).
Unfortunately, cost-effective monitoring approaches have not been developed for many of the ecosystem goods and services, which would demonstrate and quantify the many benefits and impacts of plantations. Therefore, and for many other reasons, the identification, evaluation and negotiating of trade-offs is rarely done in the process of plantation planning in the landscape.
Particularly difficult is the assessment of temporal trade-offs between short-term benefits and the long-term capacity of ecosystems to provide services to future generations (Chapin, 2009). Most measures that maintain the productive capacity of plantation systems, in particular the maintenance of soil resources, should also maintain the natural capital in the long term. However, here the interactions with other systems such as fresh water or the atmosphere also have to be considered. For example, one would have to question the usefulness of sequestering more atmospheric CO2 now by increasing plantation productivity through high use of N fertilizers which may lead to denitrification and increases in atmospheric concentrations of N2O. The latter gas has, owing to its longevity of around 120 years, an estimated global warming potential (based on a 100-year period) that is 310 times as high as that of CO2 (IPCC, 1996). Temporal trade-offs occur in particular for those ecosystem services that cannot be restored once they are lost. These include loss of species or fossil groundwater, which are at least as valuable in the future as they are now (Heal, 2000).
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