Long-Term Growth Responses of a Jeffrey Pine Stand to Mechanized Thinning and Prescribed Fire

Forest thinnings implemented with cut-to-length and whole-tree harvesting systems followed by underburning were evaluated for their effects on individual tree and stand level growth responses in pure, uneven-aged Jeffrey pine (Pinus jeffreyi Grev. & Balf.) accompanied by isolated California white fir (Abies concolor var. lowiana [Gord.] Lemm.). Based on both dimension and volume measures, trees of the unburned whole-tree treatment combination exhibited the greatest individual growth responses. At the stand level, a diminished volume growth response in the whole-tree treatment was especially pronounced in the burned portion, mostly attributable to exaggerated stocking losses, while a superior response in the unburned cut-to-length combination likely reflected not only the absence of detrimental fire impacts but also benefits of on-site slash retention. For stand level biomass, diminished growth in the whole-tree treatment was again evident, with that in the burned portion again most pronounced, while biomass accrual in the unburned cut-to-length treatment combination was generally comparable to that in the unthinned control. Increasingly utilized in forest restoration efforts in the western USA, the responses presented herein to these thinning and burning practices provide natural resource managers insight into potential compromised outcomes when implemented in Jeffrey pine and similar dry site forest types.     

An integrated assessment approach to optimal forest bioenergy production for young Scots pine stands

Background: Bioenergy is re-shaping opportunities and imperatives of forest management. This study demonstrates,through a case study in Scots pine(Pinus sylvestris L.), how forest bioenergy policies affect stand management strategies.Methods: Optimization studies were examined for 15 Scots pine stands of different initial stand densities, site types, and temperature sum regions in Finland. Stand development was model ed using the Pipe Qual stand simulator coupled with the simulation-optimization tool Opti For Bioenergy to assess three forest bioenergy policies on energy wood harvest from early thinnings.Results: The optimal solutions maximizing bare land value indicate that conventional forest management regimes remain optimal for sparse stands. Energy harvests occurred only when profitable, led to lower financial returns. A forest bioenergy policy which included compulsory energy wood harvesting was optimal for denser stands. At a higher interest rate(4 %), increasing energy wood price postponed energy wood harvesting. In addition, our results show that early thinning somewhat reduced wood quality for stands in fertile sites. For less fertile sites, the changes were insignificant.Conclusions: A constraint of profitable energy wood harvest is not rational. It is optimal to carry out the first thinning with a flexible forest bioenergy policy depending on stand density.     

Modelling the effects of forest management intensification on base cation concentrations in soil water and on tree growth in spruce forests in Sweden

The study investigated the effects of forest residue extraction on tree growth and base cations concentrations in soil water under different climatic conditions in Sweden. For this purpose, the dynamic model ForSAFE was used to compare the effects of whole-tree harvesting and stem harvesting on tree biomass and the soil solution over time at 6 different forest sites. The study confirmed the results from experimental sites showing a temporary reduction of base cation concentration in the soil solution for a period of 20–30 years after whole-tree harvesting. The model showed that this was mainly caused by the reduced inputs of organic material after residue extraction and thereby reduced nutrient mineralisation in the soil. The model results also showed that whole-tree harvesting can affect tree growth at nitrogen-poor forest sites, such as the ones in northern Sweden, due to the decrease of nitrogen availability after residue removal. Possible ways of reducing this impact could be to compensate the losses with fertilisation or extract residue without foliage in areas of Sweden with low nitrogen deposition. The study highlighted the need to better understand the medium- and long-term effects of whole-tree harvesting on tree growth, since the results suggested that reduced tree growth after whole-tree harvesting could be only temporary. However, these results do not account for prolonged extraction of forest residues that could progressively deplete nutrient pools and lead to permanent effects on tree growth.

     

Simulation of harvester productivity in selective and boom-corridor thinning of young forests

Abstract

Forest management practices may change in the future, due to increases in the extraction of forest fuel in first thinnings. Simulation models can be used to aid in developing new harvesting systems. We used such an approach to assess the productivity of innovative systems in various thinnings of young stands with wide ranges of mean breast height diameter (1.5–15.6 cm), stems per hectare (1000–19,100), and mean height (2.3–14.6 m).

The results show that selective multiple-tree-handling increases productivity by 20–46% compared to single-tree-handling. If the trees are cut in boom-corridors (10×1 or 2 m strips between strip roads), productivity increases up to 41%, compared to selective multiple-tree-handling. Moreover, if the trees are felled using area-based felling systems, productivity increases by 33–199%, compared to selective multiple-tree-handling. For any given harvesting intensity, productivity increased the most in the densest stands with small trees.

The results were used to derive time consumption functions. Comparisons with time study results suggest that our simulation model successfully mimicked productivity in real-life forest operations, hence the model and derived functions should be useful for cost calculations and evaluating forest management scenarios in diverse stands.     

Structure, allometry, and biomass of plantation Metasequoia glyptostroboides in Japan

We quantified structural features and the aboveground biomass of the deciduous conifer, Metasequoia glyptostroboides (Hu and Cheng) in six plantations in central Japan. In order to derive biomass estimates we dissected 14 M. glyptostroboides trees into three structural components (stem wood, branch wood and foliage) to develop allometric equations relating the mass of these components and of the whole tree to diameter at breast height (DBH). We found robust relationships at the branch and whole tree level that allow accurate prediction of component and whole tree biomass. Dominant tree height was similar within five older (>40 years) plantations (27–33 m) and shorter in a 20-year-old plantation (18 m). Average stem diameter varied from 12.8 cm in the youngest stand to greater than 35 cm in the oldest stand.

Metasequoia have relatively compact crowns distributed over the top 30% of the tree although the youngest stand had the deepest crown relative to tree height (up to 38%). At the individual tree level in older stands, 87% of the aboveground biomass was allocated to the stem, 9% to branch wood and 4% to foliage. We found little difference in the relative distribution of above ground biomass among the stands with the exception of lower foliage biomass in larger diameter trees. Total aboveground biomass of the older stands varied twofold, ranging from a maximum of 450 Mg ha⁻¹ in a 42-year-old stand to a minimum of 196 Mg ha⁻¹ in a 48-year-old stand. Total above ground biomass of the 20-year-old stand was 176 Mg ha⁻¹.     

Bark Beetle Demography in a Jeffrey Pine Stand as Influenced by Mechanized Thinning and Prescribed Fire

Forest thinnings implemented with cut-to-length and whole-tree harvesting systems followed by underburning were evaluated for their effects on bark beetle prevalence in pure, uneven-aged Jeffrey pine (Pinus jeffreyi Grev. & Balf.) interspersed with isolated California white fir (Abies concolor var. lowiana [Gord.] Lemm.). Based on pitch tube counts in a stand with a moderate bark beetle population in its pine component, the Jeffrey pine beetle (Dendroctonus jeffreyi Hopkins) generally preferred larger trees before treatment implementation, but after exhibiting mixed pretreatment tendencies concerning stand density demonstrated a posttreatment proclivity toward higher density. Cut-to-length thinning followed by underburning increased the pine beetle population while whole-tree thinning unaccompanied by burning reduced it. Tree mortality was induced by the bark beetle infestation but was not its sole cause. Pitch tube abundance on white fir far exceeded that on Jeffrey pine, and the greatest influence on the fir engraver (Scolytus ventralis LeConte) population was the prevalence of its host tree. The responses presented herein to these thinning and burning practices, which are being increasingly utilized in forest restoration efforts in the western USA, provide natural resource managers insight into potential forest health outcomes when implemented in Jeffrey pine and similar dry site forest types.     

Biomass and nutrients in Nova Scotian forests,and implications of intensive harvesting for future site productivity

Among four conifer and four hardwood stands in central Nova Scotia, Canada, average potential whole-tree (above-ground) harvest removals of biomass, N, P, K, Ca, and Mg were 136 000, 310, 38, 144, 360, and 39 kg/ha, respectively. These represented average increases over bole-only harvesting of 50% for biomass, 170% for N, 200% for P, 160% for K, 100% for Ca, and 120% for Mg. Thus, a moderate increase in potential biomass yield via the whole-tree harvest, was obtained at the expense of much larger increases in removals of major nutrients. On average, the whole-tree contents of biomass and nutrients were smaller than quantities present in the forest floor plus mineral soil. For biomass, the whole-tree averaged 35% the organic matter (d.w.) of the forest floor plus mineral soil, 6% of total nitrogen, 4% of total phosphorus, 1% of total potassium, 29% of total calcium, and 0.5% of total magnesium. Within this data set, only the calcium comparisons indicated a short-term cause for concern with respect to impoverishment of site nutrient capital by whole-tree harvesting.Bivariate statistical analyses of data for 12 stands and 20 variables revealed that: (i) soil organic matter and nutrient quantities were only occasionally significantly intercorrelated; (ii) quantities of biomass and nutrients in the whole-tree compartment were strongly inter-correlated with each other, but were independent of site class; and (iii) only soil K and Mg were significantly (P<0.05) but weakly (r²=−0.35) correlated with site class. Factor analysis of the same data set revealed that four multivariate factors accounted for 93% of total variance: (i) factor 1 (45% of total variance) loaded heavily on tree variables; (ii) factor 2 (an additional 18% of total variance) loaded heavily on bole and soil variables; (iii) factor 3 (an additional 16%) loaded heavily on soil variables; and (iv) factor 4 (an additional 14%) loaded heavily on soil variables, especially Ca, Mg, and K, and site class.It seems unlikely that one or several whole-tree harvests of these natural stands, if done on rotations of >ca. 50 years, would result in important depletions of site nutrient capital. However, calcium removals as a percentage of total site capital were large. This may be a cause for concern, and warrants further investigation.     

Evaluation of Mechanized Thinning and Prescribed Fire Effects on Long-Term Fuels Accumulations in Uneven-Aged Jeffrey Pine

Forest thinnings implemented through cut-to-length and whole-tree harvesting followed by underburning were evaluated for their effects on long-term downed and dead fuels accumulations in pure, uneven-aged Jeffrey pine (Pinus jeffreyi Grev. & Balf.) accompanied by isolated California white fir (Abies concolor var. lowiana [Gord.] Lemm.). Based on an initial inventory consisting of dry weight and fuel bed depth measurements conducted posttreatment, accumulations in the cut-to-length treatment were elevated according to most measures. Burned stand portions exhibited smaller quantities of fuels initially in individual timelag categories and in total as well as reduced fuel bed depths compared to their unburned counterparts except for the 1,000-hr fuels in the whole-tree treatment where postburn mortality of small stems nullified this effect. A linkage between initial mortality resulting from prescribed fire and final 1,000-hr fuels, as measured 8 yr later, was established but was probably attributable to combined thinning and burning effects. Over the course of the study, either greater accruals or diminished reductions in loading were apparent within burned stand portions compared to unburned portions, most notably in the whole-tree treatment. Results presented here provide insight into potentially compromised fuels reduction outcomes when implemented in uneven-aged stands on dry forest sites.     

Estimation of nutrient removals in stem-only and whole-tree harvesting of Scots pine, Norway spruce, and birch stands with generalized nutrient equations

Whole-tree harvesting (WTH), where logging residues are removed in addition to stems, is widely practised in Fennoscandian boreal forests. WTH increases the export of nutrients from forest ecosystems. The extent of nutrient removals may depend on tree species, harvesting method, and the intensity of harvesting. We developed generalized nutrient equations for Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies Karsten), and birch (Betula pendula Roth and Betula pubescens Ehrh.) stands to be able to calculate the amounts of nitrogen, phosphorus, potassium, and calcium in stems and above-ground biomass (stem and crown) as a function of stand volume. The equations were based on Fennoscandian literature data from 34 pine, 26 spruce, and 5 birch stands, and they explained, depending on the tree species and nutrient, 61–99% and 56–87% of the variation in the nutrient amounts of stems and above-ground biomass, respectively. The calculations based on the equations showed that nutrient removals caused by stem-only harvesting (SOH) and WTH per harvested stem m³ were smaller in pine than in spruce and birch stands. If the same volume of stem is harvested, nutrient removals are, in general, nearly equal at thinnings and final cuttings in SOH, but larger in thinnings than final cuttings in WTH. If the principal aim is to minimize the nutrient removals per harvested stem m³, the harvesting should be done at mature pine stands. The effect of biomass removal on overall site nutrient status depends on site-specific factors such as atmospheric deposition, weathering of minerals, and the size of the nutrient pools in the soil.     

Impact of silviculture on dead wood and on the distribution and frequency of tree microhabitats in montane beech-fir forests of the Pyrenees

In forest ecosystems, the level of biodiversity is strongly linked to dead wood and tree microhabitats. To evaluate the influence of current forest management on the availability of dead wood and on the abundance and distribution of microhabitats, we studied the volume and diversity of dead wood objects and the distribution and frequency of cavities, dendrothelms, cracks, bark losses and sporophores of saproxylic fungi in montane beech-fir stands. We compared stands unmanaged for 50 or 100 years with continuously managed stands. A total of 1,204 live trees and 460 dead wood objects were observed. Total dead wood volume, snag volume and microhabitat diversity were lower in the managed stands, but the total number of microhabitats per ha was not significantly different between managed and unmanaged stands. Cavities were always the most frequent microhabitat and cracks the least frequent. Dendrothelm and bark loss were favored by management. Beech (Fagus sylvatica) carried many more microhabitats than silver fir (Abies alba), especially cavities, dendrothelms and bark losses. Fir very scarcely formed dendrothelms. Secondary tree species played an important role by providing cracks and bark losses. The proportion of microhabitat-bearing trees increased dramatically above circumference thresholds of 225 cm for beech and 215 cm for fir. Firs with a circumference of less than 135 cm did not carry microhabitats. In order to conserve microhabitat-providing trees and to increase the volume of dead wood in managed stands, we recommend conserving trees that finish their natural cycle over 10–20% of the surface area.     

Changes in microclimate after stand conversion in two northern hardwood stands

Changes in air temperature, soil temperature, and soil moisture were monitored for 5 years in two northern hardwood stands after whole-tree harvesting and conversion to red pine (Pinus resinosa Ait.) plantations. Soil temperatures at a depth of 5 cm and maximum air temperatures 2 m above the soil surface were increased 5–25% after stand conversion. Soil moisture content at a depth of 5 cm was increased by 10–20% in one stand but not in the other. Differences in stand, soil, and topographical characteristics between the two stands did not have any apparent effect on the magnitude of air or soil temperature changes after stand conversion. However, higher initial stand density and soil water holding capacity appeared to be related to increased soil moisture content at one of the sites. The increased soil temperatures after conversion were not only a result of the removal of the northern hardwood canopy but also the removal and redistribution of the forest floor caused by whole-tree harvesting. Five years after stand conversion air temperature, soil temperature, and soil moisture showed no evidence of recovering from initial post-harvest levels.     

A forest biomass yield table based on an empirical model

We report an empirical model for estimating unutilized wood biomass, and its application to Cryptomeria japonica D. Don and Larix kaempferi in Tohno City, Iwate Prefecture, northeast Japan. Outputs from the model are the quantity of unutilized wood biomass and merchantable volume produced by timber harvest. The unutilized wood biomass is divided into stumps, tops, branches, foliages, small trees, and unutilized stems due to their defects. Inputs to the model are mean diameter at breast height (DBH), mean tree height, trees per unit area, and timber utilization standards. DBH distribution, DBH–height curve, stem form, bark thickness, and relationship of stem biomass to foliage and branch biomass could be described by the proposed model, indicating its validity. The proposed model enables us to develop the forest biomass yield tables modified from the existing stem volume yield tables. The developed forest biomass yield tables indicated that the unutilized wood biomass due to defects accounted for the largest part of the whole unutilized wood biomass, and that the ratio of unutilized parts in stem volume to total stem volume could vary with stand age and site productivity class. Based on a comparison of the developed forest biomass yield tables with those reported previously, we concluded that the proposed model-based forest biomass yield table would be useful for estimating the quantity of unutilized wood biomass.     

Allometry, biomass, and chemical content of Novel African Tulip Tree (Spathodea campanulata) Forests in Puerto Rico

The African tulip tree, Spathodea campanulata, the most common tree in Puerto Rico, forms novel forest types with mixtures of native and other introduced tree species. Novel forests increase in area in response to human activity and there is no information about their biomass accumulation and nutrient cycling. We established allometric relationships and chemically analyzed plant parts of African tulip trees to determine the concentration and standing stock of chemical elements (C, N, P, K, Ca, Mg, S, Mn, Al, Fe, Na), and ash. Trees ranged in diameter at breast height from 8 to 85 cm and in height from 8.8 to 28 m. The concentrations of N, P, K, and Ca in leaves of the African tulip tree were similar to those of the native pioneer Cecropia schreberiana and higher than those of mature forest tree species in Puerto Rico. The over bark wood volume of African tulip trees in nine forest stands where it was dominant ranged from 163 to 849 m³/ha. Aboveground biomass ranged from 60 to 296 Mg/ha, and N and P stocks ranged from 190 to 988 and 32 to 137 kg/ha, respectively. Novel forests on abandoned agricultural lands can store more biomass and elements than native and plantation forest stands of similar age.     

福建柏人工林生物量的研究

福建柏 (ＦｏｋｉｅｎｉａｈｏｄｇｉｎｓｉｉＨｅｎｒｙｅｔＴｈｏｍａｓ)为我国二类重点保护树种 ,其树形优美 ,主干通直 ,适应性强 ,木材性质优良 ,是我国南方值得推广的树种。由于人为破坏 ,福建柏天然纯林被毁殆尽 (张炳荣 ,1 982 )。自 50、60年代 ,福建省开始营造福建柏人工林 ,不少已进入中成龄阶段 ,成为重要的森林资源。但对其进行的研究还很少。 1 997年我们对安溪半林国有林场福建柏人工林的生物量及其结构进行了研究 ,以期对福建柏人工林的研究提供基础资料 ,也为了解福建柏人工林的生产力 ,以对其进行合理经营提供科学依据。1…     

Response of <Emphasis Type="Italic">Pinus pseudostrobus</Emphasis> Lindl. to fertile growing medium and tephra-layer depth under greenhouse conditions

Major disturbances that remove vegetation cover create conditions that differ greatly from those in adjacent forests. In volcanic areas, tephra deposition can be a major disturbance that eliminates vegetation cover and creates a barrier for plant establishment. The eruption of the Paricutín volcano, in Michoacán, México, from 1943 to 1952, created large tephra deposits adjacent to forest stands. Many of these deposits still lack native vegetation and understanding of the limiting factors for establishment of native tree species is necessary to restore these areas. Pinus pseudostrobus early growth in response to the amount of fertile growing medium on top of a variable-depth tephra layer was evaluated in a greenhouse experiment. Increasing amounts of fertile growing medium increased height of 28-week-old plants (no growing medium = 5.5 cm tall ±1.8 cm, 3 cm of growing medium = 21.2 ± 4.6 cm and 6 cm of growing medium 24.8 ± 4.4 cm). Other variables showed the same trend (diameter, number of fascicles, belowground biomass and aboveground biomass). Our results suggest that P. pseudostrobus establishment in tephra covered areas will depend on the accumulation of a fertile layer of more than 3 cm in thickness.     

Impacts of selective logging on above-ground forest biomass in the Monts de Cristal in Gabon

Selective logging is an important socio-economic activity in the Congo Basin but one with associated environmental costs, some of which are avoidable through the use of reduced-impact logging (RIL) practices. With increased global concerns about biodiversity losses and emissions of carbon from forest in the region, more information is needed about the effects of logging on forest structure, composition, and carbon balance. We assessed the consequences of low-intensity RIL on above-ground biomass and tree species richness in a 50 ha area in northwestern Gabon. We assessed logging impacts principally in 10 randomly located 1-ha plots in which all trees ?10 cm dbh were measured, identified to species, marked, and tagged prior to harvesting. After logging, damage to these trees was recorded as being due to felling or skidding (i.e., log yarding) and skid trails were mapped in the entire 50-ha study area. Allometric equations based on tree diameter and wood density were used to transform tree diameter into biomass.Logging was light with only 0.82 trees (8.11 m³) per hectare extracted. For each tree felled, an average of 11 trees ?10 cm dbh suffered crown, bole, or root damage. Skid trails covered 2.8% of the soil surface and skidding logs to the roadside caused damage to an average of 15.6 trees ?10 cm dbh per hectare. No effect of logging was observed on tree species richness and pre-logging above-ground forest biomass (420.4 Mg ha⁻¹) declined by only 8.1% (34.2 Mg ha⁻¹). We conclude from these data that with harvest planning, worker training in RIL techniques, and low logging intensities, substantial carbon stocks and tree species richness were retained in this selectively logged forest in Gabon.     

Integrated harvesting for conventional log and energy wood assortments: a case study in a pine plantation in Western Australia

Biomass or energy wood harvesting can be integrated with conventional log harvesting (saw log or pulpwood production) to allow more cost-effective energy wood supply. The efficiency of an integrated energy wood harvesting system was evaluated and compared with conventional log harvesting in a 32-year-old Pinus radiata plantation (radiata pine) located in south-west Western Australia. The harvesting system consisted of a harvester and a forwarder. The study included two treatments: a conventional log-harvesting operation where merchantable sawlogs and pulp logs were produced at the stump by the harvester and extracted by the forwarder; and an integrated energy wood operation where the harvester produced sawlogs, pulp logs and energy wood at the stump that were extracted by the forwarder. In the integrated energy wood harvesting plot, 37 m3 ha?1 of energy wood was extracted in addition to the sawlog and pulp log volumes. Extracting the additional energy wood reduced the productivity of the forwarder and increased the cost of extraction (AU$2.7?m?3) compared with the control plot (AU$2.2?m?3). Harvesting system cost was not significantly impacted, with a cost of AU$3.18?m?3 in the control plot and AU$3.23?m?3 in the integrated energy wood harvesting plot. Diameter at breast height (DBH) was a significant factor influencing the working time of the harvester, whereas load volume, extraction distance and extraction type (sawlog, pulp logs, and pulp log/energy wood) significantly impacted forwarding time. Increasing DBH resulted in longer working cycles for the harvester. Heavier loads and longer forwarding distances increased forwarding cycle time, while extracting sawlogs was least expensive and energy wood extraction was the most expensive. The marginal cost of the energy wood was approximately AU$10.2?m?3 (AU$7.0 extraction and AU$3.2 harvesting), which is about double the cost of the sawlogs. Additional material recovered in the integrated energy wood plot resulted in less residual residues on the plot (103.2 green metric tonnes per hectare [GMt ha?1]) than the control plot (144.2 GMt ha?1).     

Estimation of taper rates and volume of smaller-sized logs in spotted gum saw timber plantations in Southeast Queensland,Australia

Spotted gum (Corymbia citriodora subsp. variegata) is a popular tree species for hardwood saw timber plantations in Southeast Queensland (SEQ), Australia. In many parts of the world, logs up to 10cm top diameter are considered to be merchantable logs and acceptable at sawmills. However, due to the higher handling costs of smaller-sized logs, sawmills in SEQ are only buying logs with a top diameter of 25cm and larger. This necessitates the determination of the volume of logs with top diameters between 10 and 25cm. This paper compares the taper rates of different sizes of spotted gum logs and estimates the stem volume of spotted gum logs between 10 and 24.94cm diameter. Analysis showed that there is a statistically significant difference between the mean taper rates of bottom (30.5–64.2cm diameter) and top parts of stems (10–24.94cm diameter) at harvesting age. Using only the average taper rate of large diameter logs would underestimate the log volume of smaller-diameter logs. The average length of spotted gum logs between 10 and 24.94cm was found to be 19.27 m. Therefore, by the sawmill declining to use 10–24.94cm diameter logs, approximately 0.55m³ of log volume per tree at harvesting age would be lost.     

Effects of thinning and fertilization on wood properties and economic returns for Norway spruce

The effects of silviculture on wood and tracheid properties, and economic returns of Norway spruce (Picea abies (L.) Karst.) were investigated in two case studies, one comparing different thinning intensity in southeastern Finland and the other considering the effects of optimal nutrient addition in northern Sweden. Models for predicting the wood and tracheid properties of Norway spruce were integrated into a distance-independent process-based growth and yield model. Increasing the thinning intensity resulted in a lower mean wood density, tracheid length, and latewood proportion in harvested wood. Wood density and tracheid length of harvested pulpwood slightly decreased in later thinnings and final cuts. Thinning regimes with high early growing stock and decreasing later growing stock were most profitable. Nutrient addition accelerated volume growth and increased the value growth. The increase in volume growth due to nutrient addition more than offset the economic influence of the loss in wood density and tracheid length.     

Is the productivity decline in Norway spruce following whole-tree harvesting in the final felling in boreal Sweden permanent or temporary?

The growing demand for renewable energy sources in Sweden has resulted in an increased use of forest biomass that now includes logging residues. However, concern has been raised that the moderate increase in biomass removal associated with whole-tree harvesting results in a significant increase in nutrient removal, which in turn has a negative effect on future forest growth. Productivity over 31 years in planted Norway spruce (Picea abies (L.) Karst) in northern Sweden following three different harvest intensities is reported from a field experiment with exceptionally large growth reductions following whole-tree harvest. The three harvest intensities were applied in a randomized block design with four blocks: (i) conventional stem-wood harvest up to a top diameter of 5 cm (CH); (ii) whole-tree harvest of all above-stump biomass (WTH); (iii) branch and stem harvest with needles left on site (BSH). Recovery rate of biomass was almost 100% and the logging residues left were evenly spread over the 25- by 25-m experimental plots. Stand growth was negatively affected by WTH: basal area after 31 years was significantly lower following WTH (10.5 m² ha⁻¹) as compared to CH (14.0 m² ha⁻¹, p = 0.005) and BSH (14.2 m² ha⁻¹p = 0.003). Annual height growth of a sub-sample of trees (10 undamaged trees per plot, or 40 per treatment) was used to estimate and compare long-term effects on site productivity. This showed that stand growth loss resulted from a significant but temporary reduction in site productivity on WTH plots over a 5-year period (years 8-12, 1984-1988). Nitrogen is the major growth-limiting nutrient in boreal Swedish forests, and the N-content of needles during that period suggests that the temporal reduction in site productivity (i.e., stand growth) was primarily due to increased nitrogen loss with WTH.