Effects of shoot pruning on stem growth, needle biomass, and dynamics of carbohydrates and nitrogen in Scots pine as related to season and tree age

1990 ◽  
Vol 20 (5) ◽  
pp. 514-523 ◽  
Author(s):  
B. Långström ◽  
O. Tenow ◽  
A. Ericsson ◽  
C. Hellqvist ◽  
S. Larsson

In a field experiment in central Sweden, current shoots representing one-fifth of the needle biomass were removed from Scots pine (Pinussylvestris L.) by hand pruning young and old trees and by inducing Tomicuspiniperda (L.) (Coleoptera: Scolytidae) attacks on caged young trees. Branches in the uppermost whorls were pruned in later summer, early summer, or both. Starch and nitrogen concentrations in needles were monitored for two growing seasons. After four seasons the trees were felled and effects on growth were recorded. Starch and nitrogen concentrations in needles of pruned branches decreased and increased, respectively, compared with the controls. In old trees, but not in young ones, the raised nitrogen level persisted for 3 years after pruning. Starch and nitrogen concentrations in unpruned branches of pruned whorls did not change compared with the control until these branches became pruned, i.e., each branch acted as a semiautonomous integrated physiological unit. At felling, pruned trees were short of a portion of needle biomass equal to that removed, while at the same time, the needle biomass grown out above the pruned whorls was larger than the corresponding part of the controls. Stem volume losses in old hand-pruned trees were larger than and lasted longer than in young ones and were not yet completed four growing seasons after treatment. In a stepwise linear regression analysis, final needle biomass explained most of the total variation in volume growth of young hand-pruned trees, whereas for old trees, intertree competition was more important. Responses of beetle-pruned trees were similar to those of young hand-pruned trees. Differences in response to pruning and defoliation and in recovery between young and old trees are discussed in terms of source and sink theory and of compensatory mechanisms and carbohydrate limitation, respectively.

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1002
Author(s):  
Rafael M. Navarro-Cerrillo ◽  
Antonio Gazol ◽  
Carlos Rodríguez-Vallejo ◽  
Rubén D. Manzanedo ◽  
Guillermo Palacios-Rodríguez ◽  
...  

Systematic forest networks of health monitoring have been established to follow changes in tree vigor and mortality. These networks often lack long-term growth data, but they could be complemented with tree ring data, since both defoliation and radial growth are proxies of changes in tree vigor. For instance, a severe water shortage should reduce growth and increase tree defoliation in drought-prone areas. However, the effects of climatic stress and drought on growth and defoliation could also depend on tree age. To address these issues, we compared growth and defoliation data with recent climate variability and drought severity in Abies pinsapo old and young trees sampled in Southern Spain, where a systematic health network (Andalucía Permanent Plot Network) was established. Our aims were: (i) to assess the growth sensitivity of old and young A. pinsapo trees and (ii) to test if relative changes in radial growth were related with recent defoliation, for instance, after severe droughts. We also computed the resilience indices to quantify how old and young trees recovered growth after recent droughts. Wet-cool conditions during the prior autumn and the current early summer improved the growth of old trees, whereas late-spring wet conditions enhanced the growth of young trees. Old trees were more sensitive to wet and sunny conditions in the early summer than young trees. Old and young trees were more responsive to the Standardized Precipitation-Evapotranspiration Index drought index of June–July and July–August calculated at short (one–three months) and mid (three–six months) time scales, respectively. Old trees presented a higher resistance to a severe drought in 1995 than young trees. A positive association was found between stand defoliation and relative growth. Combining monitoring and tree ring networks is useful for the detection of early warning signals of dieback in similar drought-prone forests.


1999 ◽  
Vol 14 (1) ◽  
pp. 48-52
Author(s):  
Fabian C. C. Uzoh

Abstract The effects of competing herbaceous vegetation on the growth of ponderosa pine seedlings with and without the herbicide Pronone were characterized in this 1987-1990 study. Study areas were established in 36 plantations across western Montana on Champion International Corporation's timberland (currently owned by Plum Creek Timber Company). The study sites were divided into three precipitation classes: low, medium, and high. Mean percent stem volume growth was calculated for 3 yr by precipitation class. Split-plot analyses of variance for precipitation class, treatment, and interaction were conducted across sites between treated and untreated seedlings to test for significant (a = 0.05) differences in growth. A two-dimensional plot of precipitation class by treated versus untreated trees was constructed to show growth rate trends. After 3 growing seasons, the treated seedlings showed significantly higher stem volume growth than their untreated counterparts regardless of precipitation class. The difference between treated and untreated seedlings was statistically significant. West. J. Appl. For. 14(1):48-52.


1993 ◽  
Vol 41 (4) ◽  
pp. 291-307
Author(s):  
G. Arnold ◽  
A. Van Diest

In 1985-88, a 25-yr-old Scots pine forest in Netherlands was limed and fertilized with P, K and Mg in a factoral design. This paper addresses effects of these treatments on foliar nutrient concentrations and tree growth. Stem volume increments of individual trees were measured. Average annual volume growth was estimated to be about 16 msuperscript 3/ha, which may be a slight underestimation. P and K showed increased foliar concentrations immediately after treatment and were the only elements that significantly increased volume growth in 1988-91. Additional annual volume growth of individual trees brought about by P and K corresponded with 0.9 and 2.2 msuperscript 3/ha, respectively. Foliar Mg and Ca increased later and insignificantly reduced and increased volume growth, respectively. Lime and Mg applications tended to lower foliar N. When absolute foliar concentrations and element ratios were compared to Dutch and German standards, it appeared that application of some of these standards in present research would not always have given a fully correct prediction of growth responses to nutrient additions.


2011 ◽  
Vol 54 (1) ◽  
pp. 18-27
Author(s):  
Ando Lilleleht

Abstract. Relationships between the volume growth of mixed stands and their species composition were analyzed in order to examine the so-called “mixture effect” on stand productivity. The influence of co-species was studied using multiple linear regression analysis. Stand level basal area and height growth models were constructed in order to find out which stand characteristics can be used to describe mixture-effects. The study material originates from the Estonian network of permanent forest growth plots, only stands consisting of mainly (≥ 50% of volume) Scots Pine with Norway spruce and/or Birch spp. as co-species were used. Sample size was 139 5-year measurement periods on 88 plots; stand ages range from 14 to 167 years. The study results indicate that an increasing proportion of birch in the stand causes a negative effect on both basal area and height growth. Spruce seems to be a weaker competitor than other pines as its trend in the model is positive. Also, height growth is more rapid when the mean diameter of spruce is smaller than that of pine. Species composition coefficients for co-species (calculated by standing volume) proved to be the most significant variables that describe stand composition in the models


Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 943
Author(s):  
Katri Nissinen ◽  
Virpi Virjamo ◽  
Antti Kilpeläinen ◽  
Veli-Pekka Ikonen ◽  
Laura Pikkarainen ◽  
...  

We studied the growth responses of boreal Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) seedlings to simulated climate warming of an average of 1.3 °C over the growing season in a controlled field experiment in central Finland. We had six replicate plots for elevated and ambient temperature for each tree species. The warming treatment lasted for the conifers for three growing seasons and for the birch two growing seasons. We measured the height and diameter growth of all the seedlings weekly during the growing season. The shoot and root biomass and their ratios were measured annually in one-third of seedlings harvested from each plot in autumn. After two growing seasons, the height, diameter and shoot biomass were 45%, 19% and 41% larger in silver birch seedlings under the warming treatment, but the root biomass was clearly less affected. After three growing seasons, the height, diameter, shoot and root biomass were under a warming treatment 39, 47, 189 and 113% greater in Scots pine, but the root:shoot ratio 29% lower, respectively. The corresponding responses of Norway spruce to warming were clearly smaller (e.g., shoot biomass 46% higher under a warming treatment). As a comparison, the relative response of height growth in silver birch was after two growing seasons equal to that measured in Scots pine after three growing seasons. Based on our findings, especially silver birch seedlings, but also Scots pine seedlings benefitted from warming, which should be taken into account in forest regeneration in the future.


2021 ◽  
pp. 1-25
Author(s):  
Mandy Bish ◽  
Brian Dintelmann ◽  
Eric Oseland ◽  
Jacob Vaughn ◽  
Kevin Bradley

Abstract The evolution of herbicide-resistant weeds has resulted in the necessity to integrate non-chemical control methods with chemicals for effective management in crop production systems. In soybean, control of the pigweed species, particularly herbicide-resistant waterhemp and Palmer amaranth, have become predominant concerns. Cereal rye planted as a winter cover crop can effectively suppress early-season weed emergence in soybean, including waterhemp, when planted at a rate of 123 kg ha−1. The objectives of this study were to determine the effects of different cereal rye seeding rates (0, 34, 56, 79, 110, and 123 kg ha−1) on early-season waterhemp suppression and soybean growth and yield. Soybean was planted into fall-seeded cereal rye, which was terminated within four days of soybean planting. The experiment was conducted over the 2018, 2019, and 2020 growing seasons in Columbia, Missouri. Effects of cereal rye on early-season waterhemp suppression varied by year and were most consistent at 56 kg ha−1 or higher seeding rates. Linear regression analysis of cereal rye biomass, height, or stand at soybean planting showed inverse relationships with waterhemp emergence. No adverse effects to soybean growth or yield were observed at any of the cereal rye seeding rates relative to plots that lacked cereal rye cover. Result differences among the years suggest that the successfulness of cereal rye on suppression of early-season waterhemp emergence is likely influenced by the amount of waterhemp seed present in the soil seed bank.


The Holocene ◽  
2021 ◽  
pp. 095968362110259
Author(s):  
Anna Masseroli ◽  
Giovanni Leonelli ◽  
Umberto Morra di Cella ◽  
Eric P Verrecchia ◽  
David Sebag ◽  
...  

Both biotic and abiotic components, characterizing the mountain treeline ecotone, respond differently to climate variations. This study aims at reconstructing climate-driven changes by analyzing soil evolution in the late Holocene and by assessing the climatic trends for the last centuries and years in a key high-altitude climatic treeline (2515 m a.s.l.) on the SW slope of the Becca di Viou mountain (Aosta Valley Region, Italy). This approach is based on soil science and dendrochronological techniques, together with daily air/soil temperature monitoring of four recent growing seasons. Direct measurements show that the ongoing soil temperatures during the growing season, at the treeline and above, are higher than the predicted reference values for the Alpine treeline. Thus, they do not represent a limiting factor for tree establishment and growth, including at the highest altitudes of the potential treeline (2625 m a.s.l.). Dendrochronological evidences show a marked sensitivity of tree-ring growth to early-summer temperatures. During the recent 10-year period 2006–2015, trees at around 2300 m a.s.l. have grown at a rate that is approximately 1.9 times higher than during the 10-year period 1810–1819, one of the coolest periods of the Little Ice Age. On the other hand, soils show only an incipient response to the ongoing climate warming, likely because of its resilience regarding the changeable environmental conditions and the different factors influencing the soil development. The rising air temperature, and the consequent treeline upward shift, could be the cause of a shift from Regosol to soil with more marked Umbric characteristics, but only for soil profiles located on the N facing slopes. Overall, the results of this integrated approach permitted a quantification of the different responses in abiotic and biotic components through time, emphasizing the influence of local station conditions in responding to the past and ongoing climate change.


Author(s):  
Athanase R. Cyamweshi ◽  
Shem Kuyah ◽  
Athanase Mukuralinda ◽  
Catherine W. Muthuri

AbstractAlnus acuminata Kunth. (alnus) is widely used in agroforestry systems across the globe and is believed to provide multiple ecosystem services; however, evidence is lacking in agroforestry literature to support the perceived benefits, particularly in Rwanda. To understand carbon sequestration potential and other benefits of alnus, a household survey, tree inventory and destructive sampling were conducted in north-western Rwanda. Over 75% of the respondents had alnus trees in their farms. The trees provide stakes for climbing beans, firewood and timber. They also improve soil fertility and control soil erosion. Farmers had between 130 and 161 alnus trees per hectare with an average height of 7.7 ± 0.59 m and diameter at breast height of 16.3 ± 1.39 cm. The largest biomass proportion was found in stems (70.5%) while branches and leaves stock about 16.5 and 13% of the total biomass, respectively. At farm level, aboveground biomass of alnus trees was estimated to be 27.2 ± 0.7 Mg ha−1 representing 13.6 Mg of carbon (C) per hectare. Biomass carbon increased with tree size, from 7.1 ± 0.2 Mg C ha−1 in 3 years old trees to 34.4 ± 2.2 Mg C ha−1 in 10 years old trees. The converse was observed with elevation; biomass carbon decreased with increasing elevation from 21.4 ± 1.29 Mg C ha−1 at low (2011–2110 m) to 9.6 ± 0.75 Mg C ha−1 in the high elevation (> 2510 m). In conclusion, alnus agroforestry significantly contributes to carbon sequestration, although the magnitude of these benefits varies with tree age and elevation. Planting alnus trees on farms can meet local needs for stakes for climbing beans, wood and soil fertility improvement, as well as the global need for regulation of climate change.


Trees ◽  
2021 ◽  
Author(s):  
Hans Pretzsch

Abstract Key message Prediction of tree growth based on size or mass as proposed by the Metabolic Scaling Theory is an over-simplification and can be significantly improved by consideration of stem and crown morphology. Tree growth and metabolic scaling theory, as well as corresponding growth equations, use tree volume or mass as predictors for growth. However, this may be an over-simplification, as the future growth of a tree may, in addition to volume or mass, also depend on its past development and aspects of the current inner structure and outer morphology. The objective of this evaluation was to analyse the effect of selected structural and morphological tree characteristics on the growth of common tree species in Europe. Here, we used eight long-term experiments with a total of 24 plots and extensive individual measurements of 1596 trees in monospecific stands of European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Some of the experiments have been systematically surveyed since 1870. The selected plots represent a broad range of stand density, from fully to thinly stocked stands. We applied linear mixed models with random effects for analysing and modelling how tree growth and productivity are affected by stem and crown structure. We used the species-overarching relationship $$\mathrm{iv}={{a}_{0}\times v}$$ iv = a 0 × v between stem volume growth, $$\mathrm{iv}$$ iv and stem volume, $$v,$$ v , as the baseline model. In this model $${a}_{0}$$ a 0 represents the allometric factor and α the allometric exponent. Then we included tree age, mean stem volume of the stand and structural and morphological tree variables in the model. This significantly reduced the AIC; RMSE was reduced by up to 43%. Interestingly, the full model estimating $$\mathrm{iv}$$ iv as a function of $$v$$ v and mean tree volume, crown projection area, crown ratio and mean tree ring width, revealed a $$\alpha \cong 3/4$$ α ≅ 3 / 4 scaling for the relationship between $$\mathrm{iv}\propto {v}^{\alpha }$$ iv ∝ v α . This scaling corresponded with Kleiber’s rule and the West-Brown-Enquist model of the metabolic scaling theory. Simplified approaches based on stem diameter or tree mass as predictors may be useful for a rough estimation of stem growth in uniform stands and in cases where more detailed predictors are not available. However, they neglect other stem and crown characteristics that can have a strong additional effect on the growth behaviour. This becomes of considerable importance in the heterogeneous mixed-species stands that in many countries of the world are designed for forest restoration. Heterogeneous stand structures increase the structural variability of the individual trees and thereby cause a stronger variation of growth compared with monocultures. Stem and crown characteristics, which may improve the analysis and projection of tree and stand dynamics in the future forest, are becoming more easily accessible by Terrestrial laser scanning.


2006 ◽  
Vol 3 (1) ◽  
pp. 93-101 ◽  
Author(s):  
H. Hakola ◽  
V. Tarvainen ◽  
J. Bäck ◽  
H. Ranta ◽  
B. Bonn ◽  
...  

Abstract. The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception of weekends. Emissions were measured from two branches; one of them was debudded in May (branch A), while the other was allowed to grow new needles (branch B). The monoterpene emission pattern remained almost constant throughout the measurement period, Δ3-carene being the dominant monoterpene (50-70% of the VOC emission). The standard monoterpene emission potential (30°C) was highest during early summer in June (the average of the two branches 1.35 µg g-1h-1) and lowest during early autumn in September (the average of the two branches 0.20 µg g-1h-1. The monoterpene emission potential of branch A remained low also during October, whereas the emission potential of branch B was very high in October. The sesquiterpenes were mainly emitted during mid summer, the dominant sesquiterpene being β-caryophyllene. Branch A had a higher sesquiterpene emission potential than branch B and the emission maximum occurred concomitant with the high concentration of airborne pathogen spores suggesting a potential defensive role of the sesquiterpene emissions. The sesquiterpene emissions were well correlated with linalool and 1,8-cineol emissions, but not with monoterpenes. Sesquiterpene and 1,8-cineol emissions were equally well described by the temperature dependent and the temperature and light dependent algorithms. This is due to the saturation of the light algorithm as the measurements were always conducted during high light conditions.


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