Increasing carbon sinks through forest management: a model-based comparison for Switzerland with its Eastern Plateau and Eastern Alps

The Kyoto Protocol brought a new forest function into focus: forests as carbon sinks. This new forest function may lead to new conflicts, because on the one hand, Switzerland has decided to account for forest management under Kyoto Protocol (Article 3.4), and on the other hand, Swiss Forestry statistics and the Swiss National Forest Inventory indicate that increasing amounts of wood are being harvested. This trend seems likely to continue. In this study, we used the empirical forest model MASSIMO and the soil model YASSO to analyse four different forest management scenarios. These scenarios basically feature different levels of harvesting frequencies and different rotation length, as well as their impact on regional potentials for carbon sequestration and harvesting amounts. Results were analysed both for the whole of Switzerland and for two very different regions: The Swiss Eastern Plateau and the Swiss Eastern Alps. The results indicate that Swiss forests can provide an increasing amount of harvested wood (+18% in relation to the base year 1996) for approximately 20 years and act as a carbon sink accountable under the Kyoto Protocol (0.5 million tons carbon per year). The corresponding forest management strategy aims for a sustainable and harvestable increment and may, therefore, avoid spurious carbon maximization in forests that can happen by accounting for only forest systems, and not for the effect of substitution of non-wood products and fossil fuels by forest products. The regional results indicate that (1) the carbon sink effect of Alpine forests in Switzerland might be limited, because generally, Alpine forests have low growth and yield and (2) a large increase in harvesting may lead to regional carbon sources and necessitate regional monitoring of increment to avoid overexploitation. As MASSIMO does not include the impacts of climate change, the conclusions of this study cannot be interpreted as actual predictions into the future but portray the impact of the applied management actions on the respective trends in carbon stocks and stock changes. They are, therefore, a contribution to support future management decisions. Further studies should focus on interactions with additional forest functions such as the preservation of biodiversity, increase the consideration of forest damage and account for the effect of climate change.     

Analytical model of carbon storage in the trees, soils, and wood products of managed forests

The carbon balance between managed forests and the atmosphere depends critically on the frequency and intensity of harvesting, and the lifetime of harvested products. To assess more quantitatively the nature of this dependence, a theoretical analysis, previously applied to carbon storage in trees and wood products only, is extended here to include the carbon in forest floor detritus and soil. A dimensionless combination of the parameters of the model, alpha, with critical value alpha(c), is identified such that for alpha < alpha(c), the conversion of old-growth forest to managed forest releases carbon to the atmosphere in the long term. Parameter alpha is given by the combination f(t)D/T(*), where f(t) is the fraction of old-growth forest carbon stored in trees, D is the residence time of harvested biomass (wood products and slash debris) within the system, and T(*) is the rotation period for maximum sustained yield (maximum mean annual increment). The critical value alpha(c), typically in the range 0.5-0.7, is derived for a variety of forest types. Parameter alpha determines the degree to which the carbon accumulated in harvested biomass offsets the loss of carbon in trees due to felling and in soils due to reduced litter input. When alpha > alpha(c), long-term carbon storage is optimized by harvesting for maximum sustained yield.     

Short-term responses of ground-active beetles to alternative silvicultural systems in the Warra Silvicultural Systems Trial,Tasmania, Australia

The Warra Silvicultural Systems Trial (SST) in Tasmania, Australia provides a framework for investigating the responses of beetles (Order: Coleoptera) to three alternative systems in lowland wet eucalypt forest: aggregated retention; dispersed retention; and understorey islands retained in clearfelled areas. Beetles from three families known to be sensitive to forest management, the families Carabidae (ground-beetles), Curculionidae (weevils) and Leiodidae (fungus-beetles), were collected with pitfall traps prior to harvest, and in the first and third years post-harvest. The retained aggregates in the aggregated retention system maintained beetle assemblages reasonably typical of mature forests, at least in these early years following harvesting. These aggregates appear to provide a stable habitat, with similar species composition in the first and third years post-harvest. In contrast, the harvested areas of the aggregated retention system contained low numbers of beetle species affiliated with mature forest, as did the understorey islands and the dispersed retention system. Relative to clearfelling, all alternative silvicultural systems appeared to be of some benefit to beetles affiliated with mature forest, but aggregated retention retained far greater numbers of these beetles compared to the other systems in Tasmanian wet eucalypt forest.     

Partial cutting in mixedwood stands: Effects of treatment configuration and intensity on stand structure,regeneration, and tree mortality

In temperate and boreal mixedwood forests of eastern North America, partial disturbances such as insect outbreaks and gap dynamics result in the development of irregular forest structures. From a forest ecosystem management perspective, management of these forests should therefore include silvicultural regimes that incorporate medium- to high-retention harvesting. We present 12-year results of a field experiment undertaken to evaluate the effects of variable retention harvesting on stand structure, recruitment, and mortality. Treatments were gap harvesting (GAP), diameter-limit harvesting (DL), careful logging (CL), and careful logging followed by scarification (CL + SCAR), and an unharvested control. Although post-harvest basal area in the GAP treatment was significantly lower than that of controls, it maintained a diameter distribution profile and densities of balsam fir regeneration similar to those of pre-harvest conditions. Lower retention treatments (DL, CL, and CL + SCAR) tended to favor regeneration of pioneer, shade-intolerant species. Except for black spruce (for which mortality was highest in DL), stem mortality was similar among harvesting treatments. From an ecosystem management perspective, this study suggests that gap harvesting can maintain, in the short term, forest stand composition and structure similar to unharvested forests, and could be used where management objectives include the maintenance of late successional forest conditions.     

Silvicultural strategies for increased timber harvesting in a Central European mountain landscape

The demand for wood as construction material, renewable source for energy and feedstock for chemicals is expected to increase. However, timber increments are currently only partly harvested in many European mountain regions, which may lead to supply shortages for local timber industries, decreases in forest resistance to disturbances and functioning as protection from gravitational hazards. Using an inventory-based forest simulator, we evaluated scenarios to increase wood mobilization in the 7105-km² Swiss canton of Grisons for the period 2007–2106. Scenarios varied with respect to landscape-scale harvesting amounts and silvicultural strategies (low vs. high stand-scale treatment intensity) and accounted for regulations and incentives for protection forest management. With 50 and 100% increases of harvests, the current average growing stock of 319 m³ ha^?1 was simulated to be reduced by 12 and 33%, respectively, until 2106 in protection forests of Northern Grisons, where management is prioritized due to subsidies. Outside protection forests and in Southern Grisons, growing stock was simulated to continually increase, which led to divergent developments in forest structure in- and outside protection forests and in the Northern and Southern Grisons. The effect of silvicultural strategies on simulated forest structure was small compared to the effect of future harvesting levels. We discuss opportunities and threats of decreasing management activities outside protection forests and advocate for incentives to promote natural regeneration also outside protection forests to safeguard long-term forest stability.     

Looking deeper: An investigation of soil carbon losses following harvesting from a managed northeastern red spruce (Picea rubens Sarg.) forest chronosequence

Forest harvesting in eastern North America has been occurring for centuries but its effect on soil carbon storage and dynamics below 20 cm is not well known. This paper investigates age-related variations in carbon storage and dynamics in the organic layer and 6 depth strata in the top 50 cm of the mineral soil during ecologically important stages of post-harvest succession in a first rotation red spruce forest chronosequence that includes one of the largest old growth reference stands in northeastern North America. Storage of carbon reached a minimum 32 years post-harvest, at which time stores were approximately 50% of the intact forest. However, storage approached the range of the intact forest approximately 100 years post-harvest. Examination of age-related variations with depth revealed that concentrations of carbon below 20 cm may be driving the temporal trends in whole soil storage in these forests. Corresponding carbon isotope data were consistent with increased isotopic fractionation attributable to increased rates of mineralization post-harvest. Based on these results, we suggest that a greater emphasis should be placed upon examining storage of carbon below 20 cm in the mineral soil when evaluating the sequestration potential of intensive forest management, specifically rotation length.     

Scenario analysis of the impacts of forest management and climate change on the European forest sector carbon budget

Analysis of the impacts of forest management and climate change on the European forest sector carbon budget between 1990 and 2050 are presented in this article. Forest inventory based carbon budgeting with large scale scenario modelling was used. Altogether 27 countries and 128.5 million hectare of forests are included in the analysis. Two forest management and climate scenarios were applied. In Business as Usual (BaU) scenario national fellings remained at the 1990 level while in Multifunctional (MultiF) scenario fellings increased 0.5–1% per year until 2020, 4 million hectare afforestation program took place between 1990 and 2020 and forest management paid more attention to current trends towards more nature oriented management. Mean annual temperature increased 2.5 °C and annual precipitation 5–15% between 1990 and 2050 in changing climate scenario. Total amount of carbon in 1990 was 12 869 Tg, of which 94% in tree biomass and forest soil, and 6% in wood products in use. In 1995–2000, when BaU scenario was applied under current climatic conditions, net primary production was 409 Tg C year⁻¹, net ecosystem production 164 Tg C year⁻¹, net biome production 84.5 Tg C year⁻¹, and net sequestration of the whole system 87.4 Tg C year⁻¹ which was equal to 7–8% of carbon emissions from fossil fuel combustion in 1990. Carbon stocks in tree biomass, soil and wood products increased in all applied management and climate scenarios, but slower after 2010–2020 than that before. This was due to ageing of forests and higher carbon densities per unit of forest land. Differences in carbon sequestration were very small between applied management scenarios, implying that forest management should be changed more than in this study if aim is to influence carbon sequestration. Applied climate scenarios increased carbon stocks and net carbon sequestration compared to current climatic conditions.     

Scenario analyses for the effects of harvesting intensity on development of forest resources,timber supply,carbon balance and biodiversity of Finnish forestry

We used national scenario analyses to examine the effects of harvesting intensity on the development of forest resources, timber supply, carbon balance, and biodiversity indicators of Finnish forestry in nine 10-year simulation periods (90-year simulation period) under the current climate. Data from the 11th National Forest Inventory of Finland were used to develop five even-flow harvesting scenarios for non-protected forests with the annual harvest ranging from 40 to 100 million m³. The results show that the highest annual even-flow harvest level, which did not decrease the growing stock volume over the 90-year simulation period, was 73 million m³. The total 90-year timber production, consisting of harvested volume and change in growing stock volume, was maximized when the annual harvest was 60 million m³. Volume increment increased for several decades when harvested volume was less than the current volume increment. The total carbon balance of forestry was the highest with low volume of harvested wood. Low harvested volume increased the values of biodiversity indicators, namely volume of deciduous trees, amount of deadwood and area of old forest.     

Potential contributions of forestry and wood use to climate change mitigation in Japan

By considering trade-offs and complementarity between carbon removal from the atmosphere by forests and emission reduction by wood use, we developed a forest-sector carbon integrated model for Japan. We discuss mitigation measures for Japan based on model projections. The integrated model included the forest model and the wood use model. Based on three scenarios (baseline, moderate increase, and rapid increase) of harvesting and wood use, the integrated model projected mitigation effects including carbon removal by forests and emission reduction through the wider use of wood, until 2050. Results indicate that forests will not become a source of net carbon emissions under the three scenarios considered. The baseline scenario is most effective for mitigating climate change, for most periods. However, the sum total of carbon removal in forests and carbon emission reductions by wood use under the rapid increase scenario exceeded the one of the moderate increase scenario after 2043. This was because of strong mitigation activities: promoting replanting, using new high-yield varieties, and wood use. The results also indicated that increases in emission reduction due to greater wood use compensated for 67.9 % of the decrease of carbon removal in 2050, for the rapid increase scenario. The results show that carbon removal in forests is most important in the short term because of the relative youth of the planted forests in Japan, and that mitigation effects by material and energy substitution may become greater over the longer term.     

Moving riparian management guidelines towards a natural disturbance model: An example using boreal riparian and shoreline forest bird communities

Forest harvesting strategies that approximate natural disturbances have been proposed as a means of maintaining natural species’ diversity and richness in the boreal forests of North America. Natural disturbances impact shoreline forests and upland areas at similar rates. However, shoreline forests are generally protected from harvest through the retention of treed buffer strips. We examined bird community responses to forest management guidelines intended to approximate shoreline forest fires by comparing bird community structure in early (1–4 years) post-burned and harvested boreal riparian habitats and the adjacent shoreline forest. We sampled riparian areas with adjacent: (1) burned merchantable shoreline forest (n = 21), (2) burned non-merchantable shoreline forest (n = 29), (3) 10 m treed buffer with 25% retention in the next 30 m (n = 18), and (4) 30 m treed buffer (n = 21). Only minor differences were detected in riparian species’ abundance and bird community composition between treatments with greater differences in these parameters occurring between post-fire and post-harvest upland bird communities. Indicators of all merchantable treatments were dominated by upland species with open-habitat species and habitat generalists being typical upland indicator species of burned merchantable habitats and forest specialists typical upland indicators of harvested treatments. Riparian species indicative of burned riparian habitats were Common Yellowthroat (Geothlypis trichas), Le Conte’s Sparrow (Ammodramus leconteii) and Eastern Kingbird (Tyrannus tyrannus) and indicators of 30 m buffers were Alder Flycatcher (Empidonax alnorum) and Wilson’s Warbler (Wilsonia pusilla). Multivariate Redundancy Analysis (RDA) of the overall (riparian and upland birds) community showed greater divergence than RDA with only riparian species suggesting less effect of fire and forestry on riparian birds than on upland birds. Higher natural range of variability (NRV) of overall post-fire bird communities compared to post-harvest communities emphasizes that harvesting guidelines currently do not achieve this level of variability. However, lack of a large negative effect on common riparian species in the first 4 years post-disturbance allows for the exploration of alternative shoreline forest management that better incorporates bird community composition of post-fire riparian areas and shoreline forests.     

Modeling the effects of alternative management strategies on forest carbon in the Nothofagus forests of Tierra del Fuego,Chile

The impact of forest management activities on the ability of forest ecosystems to sequester and store atmospheric carbon is of increasing scientific and social concern. The nature of these impacts varies among forest ecosystems, and spatially and temporally explicit ecosystem models are useful for quantifying the impacts of a number of alternative management regimes for the same forest landscape. The LANDIS-II forest dynamics simulation model is used to quantify changes to the live overstory and coarse woody debris pools under several forest management scenarios in a high-latitude South American forest landscape dominated by two species of southern beech, Nothofagus betuloides and N. pumilio. Both harvest type (clearcutting vs. partial overstory retention) and rotation length (100 years vs. 200 years) were significant predictors of carbon storage in the simulation models. The prompt regeneration of harvest units greatly enhanced carbon storage in clearcutting scenarios. The woody debris pool was particularly sensitive to both harvest type and rotation length, with large decreases noted under short rotation clearcutting. The roles of extended rotations and partial overstory retention are noted for enhancing net carbon storage on the forest landscape.     

Reprint of: Lessons from long-term studies of harvest methods in southwestern ponderosa pine-Gambel oak forests on the Fort Valley Experimental Forest, Arizona, U.S.A.

The Fort Valley Experiment Station (now Fort Valley Experimental Forest) has contributed many long-term studies to forest research. This paper focuses on a “Methods of Cutting” study initiated in 1913 on the Coulter Ranch Unit of Fort Valley and how that long-term study yielded important ecological and management lessons. We quantified the historical and contemporary forest patterns at this ponderosa pine-Gambel oak site, which was harvested using three different harvesting systems in 1913 (seed tree, group selection, and light selection) and was partially excluded from livestock browsing in 1919. Using nine historically stem-mapped permanent plots for the following three stand structural scenarios: 1913 pre-harvest (modeled), post-harvest (actual), and 2003-2006 (actual) conditions, we examined the short- and long-term consequences of harvest and livestock grazing land-use and stand dynamics. We assessed changes in spatial pattern under each harvesting system and in each structural scenario, and lastly, we examined spatial and temporal tree recruitment patterns as observed in the contemporary (2003-2006) conditions. The seed tree harvests effectively converted the spatial patterns from aggregated to random and left few trees, while the group selection and light selection had varying effects, but consistently exaggerated the spatial patchiness of the stand. By 2003-2006, all plots were aggregated at all scales and were one large patch of predominately small trees. Sites that were harvested, but excluded from livestock browsing had 40% more trees in 2003-2006. Contemporary recruitment patterns were significantly aggregated under all harvesting systems, but were most strongly aggregated if the site received a group selection or light selection cut. For group and light selection, pine seedlings initially established in stump patches created by harvesting and then proceeded to fill-in the remaining area, with recruitment rarely found under the residual pine or oak trees. Long-term data sets, such as these established by the Fort Valley Experimental Forest in 1913, are essential for quantifying the impact of historical land-use practices on contemporary forest composition and structure. Ignoring land-use legacies may lead to the misinterpretation of stand dynamics and development, and therefore should be explicitly quantified and incorporated into future management and restoration activities.     

Decaying wood and tree regeneration in the Acadian Forest of Maine,USA

We examined the effect of management history on the availability of decayed downed wood and the use of downed wood as a regeneration substrate in mixed-species stands in the Acadian Forest of Maine. Regeneration of red spruce (Picea rubens Sarg.), eastern hemlock (Tsuga canadensis (L.) Carr.), balsam fir (Abies balsamea L. Mill), and red maple (Acer rubrum L.) was quantified. Treatments included variants of selection cutting, commercial clearcutting (unregulated harvesting), and no harvesting for >50 years (reference). Area of wood substrate (wood ≥ Decay Class III and ≥10 cm on at least one end) was less in the commercial clearcut than in the reference; other treatments were not differentiated. Spruce and hemlock seedlings were found at higher densities on wood than paired forest floor plots of equal area, regardless of treatment. Conversely, fir and maple were less abundant on wood than forest floor plots in reference and selection treatments, but more or equally abundant on wood than forest floor plots in the commercial clearcut. These findings suggest that silvicultural treatment affects both the availability of decayed downed wood and seedling-substrate relationships, and that forest management in the Acadian Region should consider availability of downed woody material.     

Carbon budget of Ontario's managed forests and harvested wood products, 2001–2100

Forest and harvested wood products (HWP) carbon (C) stocks between 2001 and 2100 for Ontario's managed forests were projected using FORCARB-ON, an adaptation of the U.S. national forest C budget model known as FORCARB2. A fire disturbance module was introduced to FORCARB-ON to simulate the effects of wildfire on C, and some of the model's C pools were re-parameterized using data from Canadian forests. Forest C stocks were estimated using allometric equations that represent the relationships between C and net merchantable volume and forest age based on forest inventory statistics. Other pools were included using results from ecological studies related to forest inventory variables. Data from future forest development projections adopted in approved management plans were used as model input to produce forest C budgets for the province's Crown forest management units. The estimates were extended to other types of managed forests in Ontario: parks, measured fire management zones, and private forest lands. Carbon in HWP was estimated in four categories: wood in use, wood in landfill, wood burned for energy, and C emitted by wood decomposition or burning without energy generation. We projected that the C stocks in Ontario's managed forests and HWP (in use and in landfills) would increase by 465.3 Mt from 2001 to 2100, of which 47.9 Mt is from increases in forest C and 417.4 Mt is from HWP C.     

Economic and Life-Cycle Analysis of Forest Carbon Sequestration and Wood-Based Bioenergy Offsets in the Central Hardwood Forest Region of United States

This study investigates the combined impact of carbon and bioenergy markets on upland oak dominated mixed hardwood forests in the Central Hardwood Forest Region (CHFR) of the United States. A modification of the Hartman model was used for the economic analysis of carbon sequestration and using wood-based biomass for bioenergy. A life-cycle assessment was used to determine the amount of carbon sequestered due to stand growth and emitted during harvesting and decay of wood products. Two scenarios were taken, one where additionality of carbon is considered and the other where it is not. Sensitivity analysis was done with the range of carbon and bioenergy prices. The results show that net carbon payments have more impact on land expectation value (LEV) when additionality is not considered; in contrast, bioenergy payments have more impact on LEV when additionality is considered. Carbon and bioenergy prices also influenced the amount of stand level supply of forest products and carbon in both scenarios. In general, sawtimber, wood bioenergy, and carbon supply increased with an increase in carbon prices, whereas, pulpwood supply decreased. With few exceptions at higher carbon prices, bioenergy supply decreased with the increase in wood bioenergy prices, showing a backward bending supply curve in both scenarios.     

Carbon balance of forest stands,wood products and their utilization in South Korea

Forests provide wood products and feedstock for bioenergy and bio-based products that can mitigate climate change by reducing carbon emissions. In order to assess the effects of forest products on reducing carbon emissions, we analyzed the carbon balance for individual carbon pools across the forest supply chain over a long period of time. We simulated particular forest supply chain activities pertaining to even-aged management of pine stands in South Korea to demonstrate our methods. Two different rotation scenarios (i.e., 40 and 70 years) were assessed over the 280-year time horizon in terms of temporal changes in carbon stock in each carbon pool along the supply chain, carbon transfer between carbon pools, substitution effects, and delayed carbon release by wood products. We found that the average carbon stock level was higher for the 70-year rotation scenario, but the total amount of gain in carbon was higher for the 40-year rotation at the end of the time horizon. This study confirms that forest products and energy feedstock can both reduce carbon emissions and increase carbon storage. However, the complexity of carbon accounting along the supply chain warrants a thorough evaluation from diverse perspectives when it is used to assess forest carbon management options.     

Future development of the Leningrad region forests under nature-oriented forest management

Russian forests are of high importance for the Russian economy, the European wood market, for nature conservation, and for carbon sequestration. However, the ongoing changes in forest management and administration in Russia led to uncertainty about forest ownership, wood harvesting levels, and long-term impacts of alternative management plans. Therefore, better insight in their current and future state is highly desirable. We present a study for the Leningrad region forests in which alternative management regimes for wood production and nature conservation values are balanced in varying ways. The total forest land area in the Leningrad region forest fund is 4.8 million ha. Coniferous species dominate and due to the natural succession occurring, the forests are divers in vertical structurally.

A timber assessment model was used to project the forest until 2040. Five forest management scenarios were run. Special attention was paid to a scenario that simulates recovery of the Russian forest sector in combination with the incorporation of a ‘set-aside for nature conservation’ policy. All scenarios showed that recovery of the forest sector in the Leningrad region is biologically feasible. A sustainable continuous annual production of 10.6 million m³ per year (2.8 m³ ha⁻¹ per year) by 2040 was found. The ‘Recovery with Nature Conservation’ scenario showed that recovery of the forest sector in combination with the establishment of set-aside areas is very well feasible. It was possible to set aside 28% of the forest area for nature conservation while still developing a forest sector to a production level higher than that achieved in the late eighties.

The timber assessment model applied was not specifically designed to incorporate nature-oriented forest management. We, therefore, discuss ways of improving the required methodology to analyse long-term effects of nature-oriented forest management in Europe.     

Carbon,Fossil Fuel,and Biodiversity Mitigation With Wood and Forests

Life-cycle analyses, energy analyses, and a range of utilization efficiencies were developed to determine the carbon dioxide (CO₂) and fossil fuel (FF) saved by various solid wood products, wood energy, and unharvested forests. Some products proved very efficient in CO₂ and FF savings, while others did not. Not considering forest regrowth after harvest or burning if not harvested, efficient products save much more CO₂ than the standing forest; but wood used only for energy generally saves slightly less. Avoided emissions (using wood in place of steel and concrete) contributes the most to CO₂ and FF savings compared to the product and wood energy contributions. Burning parts of the harvested logs that are not used for products creates an additional CO₂ and FF savings. Using wood substitutes could save 14 to 31% of global CO₂ emissions and 12 to 19% of global FF consumption by using 34 to 100% of the world’s sustainable wood growth. Maximizing forest CO₂ sequestration may not be compatible with biodiversity. More CO₂ can be sequestered synergistically in the products or wood energy and landscape together than in the unharvested landscape. Harvesting sustainably at an optimum stand age will sequester more carbon in the combined products, wood energy, and forest than harvesting sustainably at other ages.     

Dynamics of ecosystem services in <Emphasis Type="Italic">Pinus sylvestris</Emphasis> stands under different managements and site quality classes

Timber and biodiversity are considered two antagonistic ecosystem services (ES), largely influenced by silviculture and site ecological conditions. In order to address the trade-offs between these two ES over time, we performed a retrospective study at compartment level in the Pinus sylvestris forests of the Spanish Central Mountain System. Archival data from Management Plans for eight forests with contrasting silvicultural systems (uniform shelterwood system, group shelterwood system, irregular shelterwood system,) and three different site quality classes were analysed. Timber production was assessed through stand volume, harvested timber volume and a stand volume index. Biodiversity was examined through structural diversity (Gini index, Shannon tree size diversity index, Simpson’s reciprocal index and evenness index, all applied to diameter classes) and the abundance of large living trees. For all silvicultural systems investigated, stand volume and harvested timber volume have grown since the beginning of the management plans (beginning of the twentieth century in some forests). The largest yields of timber corresponded to the best quality sites with more intensive silvicultural treatments (uniform and group shelterwood systems). The uniform shelterwood system showed lower figures for structural diversity, though not always significant. The best site qualities maintained notable structural diversity values, even under the most intensive management system. The application of the different management systems over decades has revealed a synergy between timber production and structural diversity, particularly in those systems maintaining more than one age class, although results are conditioned by forest harvesting history. The interaction between historical silvicultural treatment and site quality has been identified as an important source of information to understand forest dynamics and functioning of ES provision.