Species mixing effects on forest productivity in the Netherlands
Lu, Huicui - \ 2017
Wageningen University. Promotor(en): G.M.J. Mohren, co-promotor(en): F.J. Sterck. - Wageningen : Wageningen University - ISBN 9789463436397 - 134
mixed forests - temperate zones - deciduous forests - soil fertility - light - yields - netherlands - gemengde bossen - gematigde klimaatzones - loofverliezende bossen - bodemvruchtbaarheid - licht - opbrengsten - nederland
Many monoculture forests (dominated by a single tree species) have been converted to mixed-species forests (dominated by more than one tree species) in Europe over the last decades. The main reason for this conversion was to increase productivity, including timber production, and enhance other ecosystem services, such as conservation of biodiversity and other nature values. In addition, it has been suggested that mixed-species forests are more resistant, resilient and stable to disturbances.
In line with the niche complementarity hypothesis, inter-specific differences in crown architecture, leaf phenology, shade tolerance and root distribution may allow tree species to partition resources in mixed forests. Such mechanisms may lead to a higher productivity of mixed forests versus monoculture forests, a phenomenon often referred to as overyielding. Interestingly, the stress-gradient hypothesis and the resource-ratio hypothesis suggests that such inter-specific interactions vary along a soil fertility gradient, but in different ways. The stress-gradient hypothesis emphasizes that more efficient partitioning increases overyielding at low fertility soils, whereas the resource ratio hypothesis considers that the denser packing of crowns on fertile soils allows for partitioning of light and overyielding on high fertility soils. Several studies have been carried out about species mixing effects on forest productivity, but so far their findings are ambiguous. Probably, this ambiguity comes from the sites that they studied, which differ in species, age, management history, and/or environmental conditions.
This thesis analyses the mixing effect on productivity in relation to the combination of species, stand age and soil fertility, and discusses possible consequences of forest management, for five two-species mixtures in the Netherlands: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)–beech (Fagus sylvatica L.), pine (Pinus sylvestris L.)–oak (Quercus robur L.), oak–beech, oak–birch (Betula pendula Roth) and pine–birch. These mixtures and their corresponding monoculture stands were studied using long-term permanent forest plots over multiple decades, but also using two inventories (around 2003 and 2013) across the entire Netherlands. These forest plots data were used together with empirical models at total stand level (chapter 2), species level (chapter 3) and tree level (chapter 4) to evaluate the mixing effect on forest productivity.
In chapter 2, four two-species mixtures and their corresponding monospecific stands were compared for productivity (volume stem wood in m3 ha-1 year-1). It was explored whether mixing species differing in leaf phenology and shade tolerance would lead to overyielding of mixed forest stands, and whether overyielding changes with stand development. In line with the niche complementarity hypothesis, the two evergreen–deciduous species mixtures (Douglas-fir–beech and pine–oak) showed overyielding whereas deciduous–deciduous species mixtures (oak–beech and oak–birch) did not. The overyielding was strongest for the Douglas-fir–beech mixture than the pine–oak mixture, which can be attributed to the greater difference in shade tolerance in the former mixture. Overyielding did not significantly change with stand development. It is argued that the regular thinning maintained the ability of species to partition resources, i.e. the complementary resource use in those mixed stands over all stand ages.
In chapter 3, it was analysed which of the two species in these four mixtures contributed to overyielding, and whether this overyielding changed along a soil fertility gradient. It was discovered that both the fast-growing and the slow-growing species could contribute to overyielding. Yet, it was mainly the fast-growing Douglas-fir that contributed to higher productivity in the Douglas-fir–beech mixtures, and the slow-growing oak that did so in the pine–oak mixtures. For both mixtures, the greatest relative productivity gain was achieved by mixtures on the poorer soils. At first sight, these results seem in line with the stress-gradient hypothesis and not the resource-ratio hypothesis. Yet, it was argued that not only complementary use of soil resources, but also use of light, may contribute to the higher productivity of mixed stands on the poorer soils.
In chapter 4, it was assessed how the growth of individual trees in mixtures was influenced by inter- and intra-specific competition, and whether this competition was mainly size-symmetric for soil resources or size-asymmetric for light on soils differing in fertility. This chapter focussed on three mixtures, i.e. oak–birch, pine–oak and pine–birch, which were available at sufficient numbers in the Dutch national forest inventory data. It was concluded that intra-specific competition was not necessarily stronger than inter-specific competition and this competitive reduction was less seen at lower soil fertility and dependent on species mixtures, which is not in line with the stress-gradient hypothesis. Moreover, size-asymmetric competition for light was more associated with tree basal area growth than size-symmetric competition for soil resources, suggesting that light is the most limiting resource. Competition for light was generally much stronger at high fertility soils, supporting the resource-ratio hypothesis. These results suggest that light is the most limiting resource for tree basal area growth and that reduced competition for light can be explained to some degree by complementarity in light use to increase tree growth in mixed forests.
This thesis thus described the productivity patterns when mixing tree species and explored possible mechanisms of higher productivity in mixed stands compared with monoculture stands in the Netherlands. Complementary use of aboveground and belowground resources probably contributes to the higher productivity in mixed stands, but other factors including pathogens, nutrient cycling and litter decomposition were not addressed but cannot be excluded. Overyielding in Douglas-fir–beech and pine–oak mixtures was maintained over time, probably owing to the intensive thinning in Dutch forests. The results shed new light on the stress-gradient and resource-ratio hypotheses. For mixtures in Dutch forest, the greatest productivity gain in Douglas-fir–beech and pine–oak mixtures was achieved on the poorer soils, and it was argued that this is at least partially driven by complementary use of light, while the role of complementarity in use of soil resources is more obscure. Overall, this thesis suggest a substantial potential of species mixing for increasing productivity, which may run in parallel with enhancing other ecosystem services such as conservation of diversity and other nature values. Yet, more experimental studies on productivity in mixed stands are required to better unravel alternative mechanisms. Such understanding is required to manage the forests effectively in a century of unpreceded human driven changes in environmental conditions.
Boomsoort, strooiselkwaliteit en ondergroei in loofbossen op verzuringsgevoelige bodem; een verkennend literatuur- en veldonderzoek
Hommel, P.W.F.M. ; Spek, T. ; Waal, R.W. de - \ 2002
Wageningen : Alterra (Alterra-rapport 509) - 112
tilia - loofverliezende bossen - vegetatie - soortendiversiteit - plantengemeenschappen - bosecologie - humusvormen - bosstrooisel - nederland - literatuuroverzichten - bodem-plant relaties - bodemchemie - bosbeheer - historische ecologie - humus - loofbos - tilia - deciduous forests - vegetation - species diversity - plant communities - forest ecology - humus forms - forest litter - netherlands - literature reviews - soil plant relationships
Dit rapport gaat in op de vraag in hoeverre de boomsoort in loofbossen op matig voedselrijke, verzuringsgevoelige bodem bepalend is voor de soortensamenstelling van de ondergroei. Om deze vraag te kunnen beantwoorden werd veld- en literatuuronderzoek verricht. Tijdens het veldonderzoek werden in zes bosgebieden de ondergroei en humusvorm onder verschillende boomsoorten maar op vergelijkbare bodem beschreven. Het literatuuronderzoek richtte zich op het Atlantisch lindewoud als historische referentie en op bestaande kennis met betrekking tot de relaties tussen boomsoort, strooiselkwaliteit en ondergroei. Geconcludeerd werd dat op bovengenoemde gronden onder bomen met rijk strooisel (o.a. linde, es en esdoorn) een gemiddeld hogere soortenrijkdom en eengroter aantal oudbossoorten voorkomt dan onder bomen met arm strooisel (o.a. eik en beuk).
Architectural approach to analysis of North American temperate deciduous forests
Oosterhuis, L. ; Oldeman, R.A.A. ; Sharik, T.L. - \ 1982
Canadian Journal of Forest Research 12 (1982). - ISSN 0045-5067 - p. 835 - 847.
centraal-amerika - loofverliezende bossen - bosbouw - noord-amerika - opstandsontwikkeling - opstandsstructuur - gematigde klimaatzones - central america - deciduous forests - forestry - north america - stand development - stand structure - temperate zones
Vegetatiekundig en oecologisch-geografisch onderzoek van het Quercion robori-petraeae in de Nederlandse zandgebieden ten Zuiden van de Waal
Bakker, J.G. - \ 1969
Wageningen University. Promotor(en): H.J. Venema. - Wageningen : Veenman - 144
loofverliezende bossen - bosecologie - historische ecologie - noord-brabant - rijk van nijmegen - gelderland - limburg - deciduous forests - forest ecology - historical ecology - noord-brabant - rijk van nijmegen - gelderland - limburg
In this thesis are given the results of an investigation of the vegetation, habitat and distribution of the Quercion robori petraeae (oak-birch-woods) in the sandy regions of N-Brabant and Limburg and in the ,Rijk van Nijmegen'. Data obtained from literature and from investigations by the author made in other parts of the Netherlands are compiled.
The investigated area, where the Quercion robori-petraeae must have dominated in the original landscape, covers:
1. North Brabant, except the holocene alluvia in the north western part and along the river Meuse;
2. North and Central Limburg, except the valley of the river Meuse (its southern limit is roughly formed by the line connecting Echt and Koningsbosch);
3. ,Rijk van Nijmegen', which comprises the municipalities of Nijmegen, Ubbergen, Groesbeek, Heumen, Overasselt and Wychen);
4. The borderland east of Brunssum and Schinveld.
To describe the Quercion robori-petraeae use has been made of ,sociological groups of species', viz. groups of species, which show a strong similarity in sociological amplitude.
In chapter two the natural condition in the investigated area is described. The climate is compared to that of the Netherlands: it is relatively warm in summer, with a gradual increase in temperature going eastwards, and relatively mild in winter with a gradual increase in temperature going westwards, while the mean annual precipitation is relatively slight, with decreasing yearly totals going eastwards (par. 2.1). The landscape, except for some peat bogs, is built up of cover sands, low terrace, push morraine, loess, blown sands derived from pleistocene riverterraces or cover sands, old pleistocene terraces and tertiary sands. Short descriptions of distribution, age, origin, topography, texture and the main soil types are given (par. 2.2).
In chapter three a general historical survey of the deciduous forests in the investigated area from the Neolithicum onwards are given. In this period deforestation began. Up to about 700 AD this process in general probably took place very gradually, but from 700-1200 AD the wooded areas were greatly reduced, corresponding with the formation of many settlements. By the late middle ages the landscape had mostly turned into vast stretches of heather, on many places alternated with sand drifts, and so it remained until far into the nineteenth century. Reforestation then started, first mostly with oak coppices, later, in the twentieth century, mostly with conifers. Much of the heaths were reclaimed and also small remnants of the original forests which mostly grew in moist to wet places in the low sandy areas, which are crossed by many brooklets. Thus the present day culture-landscape was formed. Of some of the still existing forests very old data were collected, viz. on those of the push moraine in the ,Rijk van Nijmegen' (the oldest record dates back to Roman times), the ,Echterbosch' (the oldest record is from the early middle ages), the ,Liesbosch', the ,Ulvenhoutsche Bosch' and the ,Mastbosch' (which were recorded for the first time in the late middle ages).
Chapter four deals with the classification of the Quercion robori-petreaea of the Netherlands. The chief criterium used was the floristical composition - as done is by the French-Swiss school, but the accent is placed rather on ,sociological groups of species' than on fidelity' (par. 4. 1). In par. 4.2 a survey is given of the sociological groups in which all the species in the described oak-birchwoods are arranged. To every group the sociological amplitude, the amplitude in connection with the chemical composition of the soil and with the hydrology (the most important environmental factors) and the dynamic indication are added. In par. 4.3 a historical survey of the classification of the Quercion robori-petraeae in the Netherlands is given and discussed. The following new classification is proposed:
Alliance Quercion robori-petraeae
Association Maianthemo-Quercetum ass. nov.
Sub-association Maianthemo-Quercetum anemonetosum subass. nov.
Variant with Athyrium filix-femina var. nov.
Soil: relatively very rich; (moist to) wet
Typical variant var. nov.
Soil: relatively very rich; retaining moisture to moist
Variant with Convallaria majalis var. nov.
Soil: (moderately rich to) relatively rich; dry to moisture-retaining (sometimes somewhat moist)
Sub-association Maianthemo-Quercetum typicum subass. nov.
Variant with Blechnum spicant var. nov.
Soil: moderately rich (to relatively rich); (moist to) wet
Variant with Molinia caerulea var. nov.
Soil: poor (to moderately rich); moist (to wet)
Variant with Polypodium vulgare var. nov.
Soil: poor to moderately rich; dry to moisture-retaining (sometimes somewhat moist)
Association Querceto-Betuletum TÜXEN 1930 em. DOING 1962
Variant with Molinia caerulea var. nov.
Soil: poor; moist to wet
Variant with Festuca tenuifolia var. nov.
Soil: poor; dry to moisture-retaining (sometimes somewhat moist)
In chapter five the distribution of the Maianthemo-Quercetum and the Querceto- Betuletum outside the Netherlands is given. Both associations occur chiefly in the Northern Atlantic of Europe.
In chapter six the Quercion robori-petraeae of the Netherlands is described. In par. 6.1 the vegetation-analysis is explained. The (abundance-)dominance of the author's records from the investigated area is determined with the aid of the scale Of SEGAL and BARKMAN (pg. 0 W ); for all the other records the traditional BRAUN-BLANQUET scale in six parts was used.
In the eight tables in which the floristical diversion of the variants is rendered (appendages 1-8) the species are placed in sociological groups (for the composition and sequence of these groups cf. par. 4.2) and the records according to their geographical origin, for which the following regions are distinguished (mostly plant-geographical districts or subdistricts; cf. par. 6.2):
Campine district (Ke)
Low terraces of North and Central Limburg, North-east Brabant and the ,Rijk van Nijmegen' and also the Pliocene border country east of Brunssum and Schinveld (S1)
Push moraine of the,Rijk van Nijmegen'(S2)
Veluwezoom from Doorwerth to Dieren (S3)
Eastern part of the Achterhoek (S4)
South Limburg (ZL)
Valley of the IJssel (G1)
Veluwe, Utrechtse Heuvelrug and the Gooi (G2)
Guelders Valley (G3)
Drenthian district (Dr)
Coastal area (K).
In par. 6.3 particulars on the flora of the Quercion robori-petraeae in the investigated area are given.
In par. 6.4 the different variants are described in detail. These descriptions refer to the occurrence in the investigated area in the first part and in other parts of the Netherlands in the second part.
The first part deals with:
a. Data from the vegetation-records (date and number of each record; name of the woodland and of the municipality, coordinates on the topographical map; topography; geological formation and soil type; history of the wood and the surrounding landscape).
b. Floristical survey.
c. Habitat and distribution.
The second part deals with:
a. Data from the records of the vegetation (less systematical and detailed than those of the investigated area).
b. Distribution and geographical differentiation.
In Par. 6.5 the described oak-birch-woods in the Netherlands are subjected to a closer scruting: their geographical variation is described by means of local vicariants, which are based on specific combinations of geographically differential species, or occasionnally on one such a differential species. In conclusion a survey is given of the oak-birch woods in the investigated area, which are quite possibly remnants of original forests.
Zur soziologie und Synoekologie der Buchen- und Buchenmischwaelder der nordwestdeutschen Mittelgebirge
Diemont, W.H. - \ 1938
Wageningen University. Promotor(en): J. Jeswiet. - Hannover : Floristisch-soziologischen Arbeitsgemeinschaft in Niedersachsen - 182
bosbouw - bomen - loofverliezende bossen - gebergten - duitsland - synecologie - gemengde bossen - bondsrepubliek duitsland - fagus sylvatica - gemengde opstanden - forestry - trees - deciduous forests - mountains - germany - synecology - mixed forests - german federal republic - fagus sylvatica - mixed stands - cum laude
The beech (Fagus sylvatica L.) occurs in Europe in pure and mixed mesophile, deciduous, dominantly broad-leaved forests belonging to the phytosociological order of the Fagetalia silvaticae. This order includes the true beech forests united into the Fagion alliance and is represented in the area considered by the Fagetum boreoatlanticum (with 5 subassociations), and the mixed beech forests belonging to the Fraxino-Carpinion and represented by the Querceto-Carpinetum medioeuropaeum (with 2 subassociations). A further subdivision into variants and subvariants was made.Some of the subassociations only occur on soils with a high watertable; others represent ultimate equilibrium stages in vegetational development under normal conditions, called climax vegetation types. Diemont concluded from his investigations that the climax types varied with the soil; nevertheless, within one climatic region, they were so much alike to be considered members of one climax swarm ('Klimaxschwarm'). However distinct differences between the floristic composition on northern or eastern slopes and on other slopes were found; within one region such types may be combined into one climax group ('Klimaxgruppe').Physical and chemical soil analysis supported the botanical classification. Climatic data were added. Some notes were included on the ephemeral vegetation occurring after removal of the forest.The natural forest types and the ecological conditions under which they occurred supplied valuable information on the most suitable tree and shrub species for reforestation and the treatment of the forest.