A study of tree crown characteristics and their cooling effects in a subtropical city of Australia

Abstract An evaluation of tree crown characteristics was conducted by means of a Forest Health Monitoring study in Turkey Run and Shades State Parks, Indiana. Crown dieback, foliage transparency, and crown density were summarized for three consecutive measurement years, and the short-term changes in these characteristics were quantified in an effort to identify potential forest health concerns. In both Shades and Turkey Run State Parks, no significant changes were detected in the levels of crown dieback and crown density. Only for Shades hardwoods, and more specifically hickory trees (Carya spp.), was there an unfavorable change in foliage transparency; however, this change did not appear extraordinary given the Forest Health Monitoring measurement quality objectives. This study demonstrated that given the current body of knowledge about the acceptable levels for the crown characteristics, the majority of trees in Shades and Turkey Run State Parks are not exhibiting responses to extreme stress and should be considered healthy.

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A Numerical Rating System for Crown Classes of Southern Hardwoods

Southern Journal of Applied Forestry ◽

10.1093/sjaf/25.4.154 ◽

2001 ◽

Vol 25 (4) ◽

pp. 154-158 ◽

Cited By ~ 9

Author(s):

J.S. Meadows ◽

E.C. Burkhardt ◽

R.L. Johnson ◽

J.D. Hodges

Keyword(s):

Rating System ◽

Tree Crown ◽

Direct Sunlight ◽

Individual Tree ◽

System Use ◽

Numerical Rating ◽

Crown Characteristics ◽

Time Required ◽

Total Point ◽

Stand Conditions

Abstract A numerical rating system to delineate crown classes of southern hardwoods is described. The system is based on four criteria: (1) amount of direct sunlight from above, (2) amount of direct sunlight from the sides, (3) crown balance, and (4) relative crown size. The total point value assigned places the tree within one of the four crown classes. The rating system can be used to train inexperienced hardwood foresters and should give experienced foresters a better grasp of those factors important in hardwood crown classification. Time required to evaluate a tree varies by tree, by stand conditions, and by observer, but experienced users of the system can easily rate most trees in 30–45 seconds. The rating system is particularly useful in situations where an individual tree appears to be borderline between two crown classes. For researchers, the system provides: (1) an expression of individual-tree crown characteristics, and (2) documentation of changes in crown position and condition. In two tests comparing the numerical rating system with the conventional crown classification system, use of the rating system consistently improved the ability of participants to correctly identify crown classes. Dominant and suppressed trees were the easiest to assess with the numerical rating system, whereas codominant and intermediate trees were the most difficult. Agreement between participants and experts in identification of crown classes increased with the level of the participants' forestry knowledge and experience. In one test, a group of participants attending a continuing-education hardwood shortcourse, but with little to moderate hardwood experience, correctly identified the crown class of 78% of the trees after only 1 hr of training. South. J. Appl. For. 25(4):154–158.

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A spatial statistical analysis of cork oak competition in two Portuguese silvopastoral systems

Canadian Journal of Forest Research ◽

10.1139/x02-107 ◽

2002 ◽

Vol 32 (11) ◽

pp. 1893-1903 ◽

Cited By ~ 19

Author(s):

M J Paulo ◽

A Stein ◽

M Tomé

Keyword(s):

Shape Parameter ◽

Quercus Suber ◽

Cork Oak ◽

Point Pattern ◽

Spatial Point Pattern ◽

Tree Crown ◽

Spatial Statistical Analysis ◽

Crown Shape ◽

Crown Characteristics ◽

Pattern Functions

This paper considers competition among cork oaks (Quercus suber L.) at three plots in two representative Portuguese stands. It uses spatial point pattern functions to describe densities and quantify differences among stands. Relations between cork oak characteristics and indices measuring intertree competition are modelled. Tree competition has a significant effect on tree crown characteristics. In particular, cork oaks with much competition have smaller and more elongated crowns. A standard model that relates crown diameter with diameter at breast height was improved. The R2 value increased from 0.53 to 0.63 by including a crown shape parameter and competition indices.

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Cytokinin Phytohormonal Effects on Crown Structure

Arboriculture & Urban Forestry ◽

10.48044/jauf.2016.001 ◽

2016 ◽

Vol 42 (1) ◽

Author(s):

Alisha Autio ◽

Michael Day

Keyword(s):

Cost Effective ◽

Tree Canopy ◽

Alternative Methods ◽

Cytokinin Activity ◽

Tree Crown ◽

Crown Structure ◽

Potential Applications ◽

Cost Effective Alternative ◽

Crown Characteristics ◽

Tree Care

This literature review explores the relevance of cytokinins to tree canopy form, integrating scientific research with current and potential applications to tree care methods. Current and most popular tree care methods call for growers to physically alter the shape of a tree by staking, pruning, and pinching, which can be time-consuming and expensive. Application of phytohormones (also known as plant growth regulators, PGRs) can provide ornamental growers and arborists with alternative methods to manipulate tree crown characteristics. Following a digest of the science of cytokinin activity, the review investigates the current and potential uses of phytohormones as a cost-effective, alternative method of manipulating tree shape. It discusses how the different forms of cytokinin PGRs, acting alone and in concert with other PGRs, can be used, what they can be used for, methods of application, and timing of applications within the phenological cycles of trees. By integrating current basic and applied literature, the review seeks to summarize understanding of cytokinin regulation of crown structure, while exploring potential applications in the tree care industry.

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Basic density and crown parameters of forest forming species within Steppe zone in Ukraine

Folia Oecologica ◽

10.2478/foecol-2018-0009 ◽

2018 ◽

Vol 45 (2) ◽

pp. 82-91

Author(s):

Svitlana Sytnyk ◽

Viktoriia Lovynska ◽

Petro Lakyda ◽

Katerina Maslikova

Keyword(s):

Scots Pine ◽

Prediction Models ◽

Black Locust ◽

Robinia Pseudoacacia ◽

Basic Density ◽

Steppe Zone ◽

Tree Crown ◽

Crown Volume ◽

Branch Biomass ◽

Crown Characteristics

Abstract The parameters of wood density (WD), bark density (BD) and tree crown characteristics are not only important for estimation of the aboveground biomass, but they also serve as indicators for the timber quality. This study had two objectives: Black locust (Robinia pseudoacacia L.) – an introduced species; Scots pine (Pinus sylvestris L.) – an aboriginal species. Black locust and Scots pine from the Steppe zone in Ukraine were compared in their WD and BD, and in the morphological parameters of their tree crowns. There were determined basic WD and BD for differently aged individuals of Black locust and Scots pine. Generally, a higher WD was found for Black locust trees. The average Black locust WD was 518 kg m−3, ranging from 375 kg m−3 to 612 kg m−3; with the average BD – 294 kg m−3, ranging from 214 kg m−3 to 421 kg m−3. The average Scots pine WD was 414 kg m−3, ranging from 254 to 491 kg m−3; with average BD – 317 kg m−3, ranging from 178 to 433 kg m−3. The dependences between WD, BD and biometric tree parameters were identified by correlation analysis. The crown diameter for Black locust and Scots pine was described with fixed prediction models. We proposed particular equations for relationships between foliage biomass and branch biomass, derived from the crown volume of the investigated species.

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