Search

Background: Tree ontogeny is the genetic trajectories of regenerative processes in trees, repeating in time and space, including both development and reproduction. Understanding the principles of tree ontogeny is a key priority in emulating natural ecological patterns and processes that fall within the calls for closer-to-nature forest management. By recognizing and respecting the growth and development of individual trees and forest stands, forest managers can implement strategies that align with the inherent dynamics of forest ecosystem. Therefore, this study aims to determine the ontogenetic characteristics of tree regeneration and growth in northern European hemiboreal forests., Methodology: We applied a three-step process to review i) the ontogenetic characteristics of forest trees, ii) ontogenetic strategies of trees for stand-forming species, and iii) summarise the review findings of points i and ii to propose a conceptual framework for transitioning towards closer-to-nature management of hemiboreal forest trees. To achieve this, we applied the super-organism approach to forest development as a holistic progression towards the establishment of natural stand forming ecosystems., Results: The review showed multiple aspects; first, there are unique growth and development characteristics of individual trees at the pre-generative and generative stages of ontogenesis under full and minimal light conditions. Second, there are four main modes of tree establishment, growth and development related to the light requirements of trees; they were described as ontogenetic strategies of stand-forming tree species: gap colonisers, gap successors, gap fillers and gap competitors. Third, the summary of our analysis of the ontogenetic characteristics of tree regeneration and growth in northern European hemiboreal forests shows that stand-forming species occupy multiple niche positions relative to forest dynamics modes., Conclusions: This study demonstrates the importance of understanding tree ontogeny under the pretext of closer-to-nature forest management, and its potential towards formulating sustainable forest management that emulates the natural dynamics of forest structure. We suggest that scientists and foresters can adapt closer-to-nature management strategies, such as assisted natural regeneration of trees, to improve the vitality of tree communities and overall forest health. The presented approach prioritizes ecological integrity and forest resilience, promoting assisted natural regeneration, and fostering adaptability and connectivity among plant populations in hemiboreal tree communities., Competing Interests: The authors declare that they have no competing interests., (© 2024 Petrokas et al.)

In order to achieve sustainable food production, non-chemical weed management practices need to be developed for fruit growing. Tailor-made floor management systems enable efficient weed regulation, but they also affect the soil quality in an orchard. In this article, the effects of various floor management systems in a 'Red Jonaprince' apple (Malus × domestica Borkh.) orchard on the soil properties and the trees' nutritional status and initial development during the first two years after the orchard's establishment were assessed. The experiment was set up in the spring of 2017 in the Experimental Orchard of WULS. 'Red Jonaprince' cv. trees grafted on M.9 rootstock were planted with 3.5 × 1 m spacing between them. Different floor management systems were applied to the rows, including the selected organic mulches: Miscanthus × giganteus straw (MG1 and MG2), spent mushroom substrates (SMS1 and SMS2), herbicide strip (HS), clear mechanical soil cultivation (MC), and synthetic black mulch (BC). The organic mulches affected the soil properties significantly. Spent mushroom substrates (SMS1, SMS2) increased the P and K contents in the soil, increased the salinity 10-fold, and retarded the growth in terms of the trunk cross-section area (TCSA) and its increment compared with other systems. Miscanthus × giganteus straw mulch (MG1, MG2) was associated with a more vigorous shoot growth compared with other combinations in the first year of the study as it provided a better tree nitrogen nutritional status. The floor management system affected the generative development of the trees. Mulching with a spent mushroom substrate boosted the flower bud formation intensity, but it did not affect the yielding quantity. Moreover, due to the poor fruit set, the trees mulched with a spent mushroom substrate (SMS2) gave a low initial bearing. High crop loads were noted for the trees treated with black synthetic mulch (BC) and the trees mulched with Miscanthus × giganteus straw (MG1). This was an effect of the tree size rather than the blooming intensity, while there were no differences in the cropping efficiency index (CEI) parameter. [ABSTRACT FROM AUTHOR]

Planning the sidewalk afforestation composition is critical to understanding tree development over time, as well as enabling trees to deliver their many quality benefits. The objective of this work was to evaluate the number of small, medium and large-sized tree species during eight growth projection moments on the streets of Irati city- PR. Different streets with and without power grids and streets with sidewalks larger and smaller than three meters were evaluated by counting the number of suitable trees in the appropriate spaces and the average increase in crown area of Lagerstroemia indica, Handroanthus albus and Paraptadenia rigida, over 5, 10, 15, 20, 25, 30, 35 and 40 years of growth projection. Data was transformed to attend the normality criteria and compared by the Tukey test at 5% probability, using an experimental design in subdivided plots. There was a significant difference and interaction between species size and projection time. The large-sized species presented higher increase in crown area throughout the years, despite the smaller number of trees that could be planted. This kind of species is advised for planting as long as proper maintenance is considered for trees to provide maximum benefits. [ABSTRACT FROM AUTHOR]

Tree biomechanics and biomechanical tree stability are research problems that have been discussed in world literature for many years. The biomechanical profile formation in trees is an extremely complicated problem and has not been fully clarified to date. It is influenced by many factors, which determine tree growth, tree development, multifunctionality of organs, and anatomical elements in xylem. The phenomenon is further affected by the overlapping of functions and development of numerous interactions between all the systems found in living trees. This paper presents a synthetic description of selected research results, providing insight into the mechanical functioning of trees, from initial theories of mechanical tree formation to the influence of dynamic load on tree stability. Trees are a biological structure that shows high adaptability to external conditions. Thus, the response to a specific environmental stressor, including abiotic and biotic factors, should be considered. Analyses of the biomechanical system in plants need to be considered in a broader context than a selected single load. Due to the complexity of these phenomena and numerous interactions, we need more multidisciplinary research to explain biomechanical mechanism of tree development. [ABSTRACT FROM AUTHOR]

Even-aged forest stands are competitive communities where competition for light gives advantages to tall individuals, thereby inducing a race for height. These same individuals must however balance this competitive advantage with height-related mechanical and hydraulic risks. These phenomena may induce variations in height-diameter growth relationships, with primary dependences on stand density and tree social status as proxies for competition pressure and access to light, and on availability of local environmental resources, including water. We aimed to investigate the effects of stand density, tree social status and water stress on the individual height-circumference growth allocation (Δh-Δc), in even-aged stands of Quercus petraea Liebl. (sessile oak). Within-stand Δc was used as surrogate for tree social status. We used an original long-term experimental plot network, set up in the species production area in France, and designed to explore stand dynamics on a maximum density gradient. Growth allocation was modelled statistically by relating the shape of the Δh-Δc relationship to stand density, stand age and water deficit. The shape of the Δh-Δc relationship shifted from linear with a moderate slope in open-grown stands to concave saturating with an initial steep slope in closed stands. Maximum height growth was found to follow a typical mono-modal response to stand age. In open-grown stands, increasing summer soil water deficit was found to decrease height growth relative to radial growth, suggesting hydraulic constraints on height growth. A similar pattern was found in closed stands, the magnitude of the effect however lowering from suppressed to dominant trees. We highlight the high phenotypic plasticity of growth in sessile oak trees that further adapt their allocation scheme to their environment. Stand density and tree social status were major drivers of growth allocation variations, while water stress had a detrimental effect on height in the Δh-Δc allocation. [ABSTRACT FROM AUTHOR]

The author reflects on the study by R. Trouvé and colleagues on the relationship between sessile oak trees' diameter growth rates and height growth rates. The study reportedly involved data sets from long-term experiments of sessile oaks and involved pooled analysis of the diameter-height relationship. The results reportedly revealed that the maximum height growth rate was greater in sparsely managed stands compared with densely managed stands.

The article examines a novel hemisphere-dependent leaning habit in Araucaria columnaris (Cook pine) in New Caledonia. Complex interactions of genetics and environmental stimuli in a tree's form, is determined. Also investigated is the relationship between magnitude of lean and latitude across regional samples in the country.

One of the determining factors in urban tree development and growth is fertilization. We therefore studied the nutritional requirements of five tree species used in urban forestry (Tabebuia chrysantha, Margaritaria nobilis, Hamelia patens, Apeiba aspera, Cupania americana) using the missing element technique. Differential responses by groups were found for nitrogen and sulfur deficiencies. The T.chrysanta, M.nobilis, and H.patens groups showed high sensitivity to nitrogen deficiencies. This was evident in a lower mean growth for all variables assessed: height, root neck diameter, aerial dry matter, and radical dry matter. The C. americana and A. aspera group showed the lowest mean growth for sulfur deficiencies. The HJ-Biplot representations, used to characterize the species' response to each treatment, showed low growth yields for nitrogen and sulfur deficiencies in every individual tree species assessed. The imbalance of calcium/magnesium bases and magnesium/potassium bases affected height growth in all species. This was evident in the high growth obtained for the calcium- and magnesium-deficient treatments. The treatments that added calcium and/or magnesium accentuated the imbalance and gave low growth in all variables. [ABSTRACT FROM AUTHOR]

With the objective of characterizing the best-performance accessions under nursery conditions, a Leucaena spp. collection, represented by 23 accessions of five species, was evaluated. For that purpose the following elements were measured: seedling height, stem diameter and branch number, dry biomass of the aerial part, root length and dry matter, which served as indicators of the optimum transplantation moment; the seedlings were planted in 26 x 14 cm black polyethylene bags. These features were observed to have remarkable influence on plant development and when a main component analysis was applied, they showed high variability (63,10%) in the first component. Relation was found among plant height, number of leaf growths, dry biomass of the aerial part, dry root mass and root length, and for these features the following accessions stood out: L. leucocephala cv. Cunningham, cv. Peru, CIAT-9119, CIAT-9438, CIAT- 751, CIAT-7988, CIAT-7384, CIAT-7929, CIAT-17480, cv. Ipil-pil, cv. CNIA-250; L. lanceolata CIAT-17255, CIAT- 17501 and L. diversifolia CIAT-17270. It is concluded that there was variability in the collection among the species and among the accessions of each species, and that it is necessary to take into consideration the studied characteristics to define the optimum transplantation moment. [ABSTRACT FROM AUTHOR]

The performance of 60 accessions was studied under nursery conditions, with the objective of characterizing forage trees and shrubs and further evaluating the possible variations among species. According to the main component analysis there was a high variability (36%) in the first component and the indicators initial height, stem diameter, height 90 days after planting and pest incidence contributed to it. In addition, a good part of this percentage was also explained by the contribution of diseases (plane CP1-CP3). From the six groups formed, IV and VI (L. longistylus, Schizolobium sp., M. nigra and T. gigantea) showed 63% positive contribution of the variables; while the accessions in group I were the less outstanding. Germination, survival and stem diameter were concluded to have high influence on the development of seedlings in the nursery stage, for which, together with the indicator plant height, they should be taken into consideration to determine the optimum moment of transplantation. L. longistylus, Schizolobium sp., M. nigra and T. gigantea were the most outstanding species regarding the studied characters. [ABSTRACT FROM AUTHOR]

Embryogenic cultures (EC) of Anatolian black pine (Pinus nigra J.F.Arnold subsp. nigra var. caramanica (Loudon)Businsky) were initiated from immature pre-cotyledonary zygotic embryos sampled weekly from 16 different trees in 2 consecutive years. Douglas-fir cotyledon revised (DCR) medium supplemented with 13.6 μM of 2,4-D and 2.2 μM of BAP was used for initiation and maintenance of EC. Overall initiation frequencies of EC in the study were 0.92% in 2004 and 1.96% in 2005; tree values ranged from 0.0% to 7.32%. Overall, 0.38% and 0.62% of the initial explants were converted into established cell lines in 2004 and 2005, respectively. [ABSTRACT FROM AUTHOR]

We analyzed the growth patterns of Thujopsis dolabrata var. hondai trees in an old plantation (161 years old), where no silvicultural treatments (e.g., thinning) have been conducted since the initial planting. The analysis focused on understanding individual growth under a long-term self-thinning process, and the stand-level stemwood production at the mature stage was evaluated. Nine canopy-layer trees and one suppressed tree were used for the analysis of annual increments in stem diameters, heights, and stemwood volumes for a given past year using the ring-width data. Both the diameter (at basal portion) and height of all the canopy-layer trees increased at similar rates during the early stage (i.e., 60–70 years after planting); however, after this period, only the height growth rates declined sharply. The annual growth rates of stemwood volume also simultaneously leveled off at the stand age of 40–60 years. Subsequently, the patterns diverged conspicuously, e.g., the growth rates were maintained or increased in some individuals, while it gradually decreased in the case of others until the present year. The divergence of growth pattern was likely to be triggered by intertree competition at several decades after the onset of canopy closure. The current stemwood production of the sample trees, including the suppressed one, was positively correlated with certain size parameters such as stem diameter at breast height and sapwood area at a height of 4 m. Based on the diameter-base allometry, the total stand stemwood production was estimated to be about 12.8 m3 ha−1 year−1. This estimate was higher than those of some old natural T. dolabrata forests (2.0–8.6 m3 ha−1 year−1) that have been well managed by repetitive selection thinning. Furthermore, individual mean stemwood production of the study plantation (0.03 m3 tree−1 year−1) was within the range of these natural stands (0.01–0.05 m3 tree−1 year−1). These comparisons suggested that the old T. dolabrata plantation still maintained a relatively high stemwood production potential despite the absence of artificial controls of tree density in the past. In terms of timber production, this fact implied that a rather long rotation (>100 years) can be applicable in the management of T. dolabrata plantations. [ABSTRACT FROM AUTHOR]

In closed-canopy forests, plant morphology and physiology determine shade tolerance and potential growth and mortality rates; potential vital rates and ongoing gap dependence determine realized vital rates; and realized vital rates determine individual size distributions. This hypothesis was evaluated for the 73 most abundant canopy tree species from Barro Colorado Island, Panama. The percentage of recruits located in tree-fall gaps (P), sapling growth (G), and mortality (M) rates, and the coefficient of skewness of size distributions (g1) were determined from censuses of all individuals >10 mm dbh in a 50- ha plot. Seven qualitative, bivariate predictions relating g[sub1], G, M, P, and wood density (W) were evaluated. Six of the seven predictions were substantiated in pairwise analyses. A path analysis integrated all seven predictions and explained 51% of the interspecific variation in g[sub1]. Size distributions with many large individuals and a long tail of relatively rare, small individuals (g[sub1] < 0) characterized gap-dependent species with large fecundity, seed mortality, seedling mortality, G, M, and P. Size distributions with many small individuals and a long tail of relatively rare, large individuals (g[sub1] > 0) characterized shade-tolerant species with the opposite traits. The percentage of tropical tree species that require tree- fall gaps to regenerate has been estimated to range from <20% to >70% for old-growth forests. [ABSTRACT FROM AUTHOR]

The author discusses a study she conducted with other researchers concerning the capability of oak transplantation to save trees. The results revealed instability in the strength of transplanted trees. Oak trees are reportedly keystone species because they provide for the life cycle needs of other trees. It is concluded that oaks evolved to stay in one place for their whole lifetime like all other trees.

With the objective of characterizing the best-performance accessions under nursery conditions, a Leucaena spp. collection, represented by 23 accessions of five species, was evaluated. For that purpose the following elements were measured: seedling height, stem diameter and branch number, dry biomass of the aerial part, root length and dry matter, which served as indicators of the optimum transplantation moment; the seedlings were planted in 26 x 14 cm black polyethylene bags. These features were observed to have remarkable influence on plant development and when a main component analysis was applied, they showed high variability (63,10%) in the first component. Relation was found among plant height, number of leaf growths, dry biomass of the aerial part, dry root mass and root length, and for these features the following accessions stood out: L. leucocephala cv. Cunningham, cv. Peru, CIAT-9119, CIAT-9438, CIAT-751, CIAT-7988, CIAT-7384, CIAT-7929, CIAT-17480, cv. Ipil-pil, cv. CNIA-250; L. lanceolata CIAT-17255, CIAT-17501 and L. diversifolia CIAT-17270. It is concluded that there was variability in the collection among the species and among the accessions of each species, and that it is necessary to take into consideration the studied characteristics to define the optimum transplantation moment. [ABSTRACT FROM AUTHOR]

• A long-term urban tree cohort was monitored for 39 years. • The street tree preservation program effectively preserves urban trees. • Street tree preservation resulted in a 6:1 (benefit/cost) return on investment. • A trees and construction program and policies promote urban forest sustainability. A long-term research study in Milwaukee, Wisconsin, USA investigated how construction (i.e., repairs to streets, curbs, and sidewalks) affected tree condition, survival, and growth compared to control trees outside construction zones and effects of a tree preservation program on reducing construction impacts. This study is divided into three periods: (1) a limited implementation period (1979–1989) prior to a formal tree preservation program, (2) an intermediate implementation period (1989–2005) during the development and refinement of a tree preservation program, and (3) a full implementation period (2005–2018) after comprehensive execution of the tree preservation program. During the initial limited preservation period, baseline measurements from 1989 showed trees in construction zones died at a higher annual rate (4.1% actual) and had a lower tree condition rating (5.7% actual) in the limited implementation period (1979–1989) as compared to the other two periods. During the intermediate implementation period (i.e. program under development), construction activities resulted in a reduced effect on tree condition (2.4% actual) as measured in 2005. Tree survival and condition in the full implementation period were similar between trees associated with construction zones and non-impacted control trees measured in 2018. Results demonstrate the effect of a tree preservation program on promoting healthy trees in construction zones. Significant findings also show the importance of growing space with trees farther away from curbs and sidewalks having a higher tree condition and survival rate in all three periods. Findings from this study can encourage city-wide-preservation programs elsewhere to protect public street trees from construction. [ABSTRACT FROM AUTHOR]

• H N and H N:P were measured in each organ for young trees. • H P and H N:P were determined in each organ in mature trees. • Leaf H N:P of mature trees was greater than that of young trees. • H differed among organs in mature trees, not in young trees. • N was limited for young trees and P was limited for mature trees. The degree of stoichiometric homeostasis can be indicated by the homeostatic coefficient (H), which reflects the ability of plants to maintain a stable nutrient composition regardless of changes in environmental nutrients. In previous studies, H had been determined primarily in herbs and varied significantly among organs and growth stages. However, whether H varies according to organ-type and age in tree species is unknown. In this study, nitrogen (N) and phosphorus (P) fertilization experiments were conducted in young and mature Metasequoia glyptostroboides plantation stands. The H of N (H N) and H of N:P (H N:P) was found in young trees, H of P (H P) and H N:P existed in mature trees. Also, leaf H N:P of mature trees was greater than that of young trees (P < 0.05), and H showed significant difference among organs in mature trees (P < 0.05), but not in young trees (P > 0.05). Thus, stoichiometric homeostasis varied with tree age and among organs, and leaf N:P was more tightly constrained in mature trees than in young trees. These findings imply that stoichiometric homeostasis is coupled to tree growth and development, which suggest N limitation for young trees and P limitation for mature trees, at least in M. glyptostroboides. [ABSTRACT FROM AUTHOR]

The article presents information on the growth of a giant sequoia growing in Sequoia National Park, California. The massive conifer, named General Sherman in 1879, is the world's largest tree. It measures 82m and 9m across at the base. It is estimated that the tree is even younger, 2,100-2,200 years old. The Sherman tree is very bulk. It is more than 10 times larger than a blue whale. Researchers are indicating the extremely large trees are not necessarily the oldest. From tree rings in cut sequoia stumps it is clear that the sequoias that is much smaller than the Sherman tree have reached ages of more than 3,200 years. Each year the Sherman tree grows by adding wood to make a tree 30 cm in diameter and more than 30m tall. The analysis is based on tree-ring measurements from pencil-thin, 30 cm cores of wood that was removed from the area near the base of the Sherman tree.