A silvicultural stand density model to control understory in maritime pine stands

Fonseca, Teresa; Duarte, Juan Carlos Santos

doi:10.3832/ifor2173-010

Cited by 19 publications

(18 citation statements)

References 18 publications

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“…Management practices should adapt and spatially diversify the structure of the forests to make them less prone to the risk of wildfires [41]. At the forest scale, typical forest management practices, such as the management of stand density [42], through thinning and harvesting systems, can contribute to reducing wildfire risk through the decrease of fuel loads [43]. These silvicultural practices can be supported by the self-thinning model proposed in the current study, serving as adaptive guidelines in the management of these pine systems.…”

Section: Size-density Trajectory and Self-thinning Linementioning

confidence: 99%

Size–Density Trajectory in Regenerated Maritime Pine Stands after Fire

Enes

Lousada

Aranha

et al. 2019

Forests

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Research Highlights: This study bridges a gap of knowledge about the maximum size-density trajectory for juvenile stands of maritime pine. The continuity of the trajectory along the development stages to maturity is assured with a straightforward approach providing support to determine optimum density along all the revolution periods for the species. Background and Objectives: Forest fire is a significant threat to forests in the Mediterranean regions, but also a natural disturbance that plays a vital role in the perpetuation of forest stands. In recent decades, there has been an increase of burnt area in maritime forests in Portugal, followed by an increased interest in managing the natural and usually abundant regeneration occurring after the fires. The gap in the knowledge of growth dynamics for juvenile stages, for these forest systems, currently constrains their correct management, for forest planning, particularly in determining the optimal densities. The study aims to identify the maximum attainable density trajectory at the early stages of development of the species that could support a non-empirical definition of silvicultural prescriptions and thinning decisions, along the revolution. Materials and Methods: A representative data set collected in stands regenerated after fire supports the analysis of the maximum size-density trajectory for the species. Results: The maximum size-density trajectory for the juvenile stands deviates from the expected trajectory defined in the self-thinning line published for the species. Significant deviation occurs at the lower end of the line, indicating the need for a reevaluation of the existing self-thinning line. We propose a new self-thinning model for the species that explicitly considers the behavior of size-density for juvenile stands. The new model assures a logical continuity for the trajectory from the young stages of development to maturity. Conclusions: The proposed model based on the maximum attainable size-density trajectory provides ecological-based support to define silvicultural guidelines for management of the species.

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Section: Size-density Trajectory and Self-thinning Linementioning

confidence: 99%

Size–Density Trajectory in Regenerated Maritime Pine Stands after Fire

Enes

Lousada

Aranha

et al. 2019

Forests

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“…This results in a lower CR due to a narrower and smaller crown depth. Since the information of HDOM and stand stocking (N ha −1 ) is included in the RSI, this index can be applied for the evaluation of thinning specification, which is based on the information of both site quality class and stand development stage [11,76]. Diameter and height growths are associated with the effects of stand density and crown sizes.…”

Section: Discussionmentioning

confidence: 99%

“…We also calculated the relative spacing index (RSI), which is defined by RSI = √ 10, 000/N/HDOM [11,20,74,75]. We assumed RSI as an effective stand density measure for determining the thinning specification, because it includes stocking and combined effect of site quality and stand development stage through N and HDOM, respectively [11,44,76].…”

Section: Tree and Stand Measuresmentioning

confidence: 99%

Generalized Nonlinear Mixed-Effects Individual Tree Crown Ratio Models for Norway Spruce and European Beech

Sharma

Vacek

2018

Forests

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Tree crowns are commonly measured to understand tree growth and stand dynamics. Crown ratio (CR—crown depth-to-total height ratio) is significantly affected by a number of tree- and stand-level characteristics and other factors as well. Generalized mixed-effects CR models were developed using a large dataset (measurements from 14,669 trees of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica (L.)) acquired from permanent research plots in various parts of the Czech Republic. Among several tree- and stand-level variables evaluated, diameter at breast height, height to crown base, dominant height, basal area of trees larger in diameter than a focal tree, relative spacing index, and variables describing the effects of species mixture and canopy height differentiation significantly contributed to CR variation. We included sample-plot-level variations caused by randomness in the data and other stochastic factors into the CR models using the mixed-effects modeling approach. The logistic function, which predicts the values between 0 and 1, was chosen to develop the generalized CR mixed-effects model. A large proportion of the CR variation (R2adj ≈ 0.63 (Norway spruce); 0.72 (European beech)) was described by generalized mixed-effects model without significant residual trends. Testing the CR model against a part of the model fitting dataset confirmed its high prediction precision. Our CR model can be useful for growth simulation using inventory databases that lack crown measures. Other potential implications of our CR models in forest management are mentioned in the article.

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“…The inability of seedlings to grow to reach the sapling stage is allegedly due to competition for resources such as sunlight, water, and soil nutrient needs. The overstory canopies of the primary forest are relatively tight, that can reduce the existing understory vegetation (Botequim et al, 2015;Fonseca & Duarte, 2017).…”

Section: A Kabesak Abundance In Each Type Of Landmentioning

confidence: 99%

Stand and Site Characteristics of Kabesak (Acacia leucophloea) in Timor Island, East Nusa Tenggara, Indonesia

Hendrik¹,

Kusmana²,

Muhdin³

2019

JPKW

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Kabesak (Acacia leucophloea) is a particular plant species and recognized to have important benefits to the local people of Timor Island. The people of Timor Island use kabesak leaves as animal feed in the dry season and kabesak wood is used as building materials and furniture. The purpose of this study was to determine the stand and site characteristics of kabesak in the western region of Timor, Indonesia. The means of density, frequency, dominance, and importance value index were analyzed. The results showed kabesak stand structure in secondary forest land, grassland, and shrubs, as well as garden showed the J-inverted shaped, which implies that natural regeneration was a proper continuation. Kabesak had significant associations with a few plants' species, both negative and positive types. The result of regression analysis of the principal components showed that the contribution of edaphic factor influences the population density of kabesak. Silt fraction and phosphorus content were found to have the highest positive effect on the density, while sand fraction and sodium content were found to have the highest negative effects of kabesak. A test for altitude with Tukey test (α = 0.05) reveals that kabesak from 0-300 m a.s.l., 300-600 m. asl., 600-900 m a.s.l. were not different from each other, while altitude >900 m a.s.l. was significantly different from the other groups. ABSTRAKKabesak (Acacia leucophloea) adalah spesies tanaman yang dikenal memiliki manfaat penting bagi penduduk lokal Pulau Timor. Masyarakat Pulau Timor memanfaatkan daun kabesak sebagai pakan ternak di musim kemarau dan kayunya dimanfaatkan sebagai bahan bangunan dan meubel. Tujuan dari penelitian ini adalah untuk menentukan karakteristik tegakan dan tempat hidup kabesak di wilayah Timor Barat, Indonesia. Penelitian ini dianalisis dengan menggunakan indeks kepadatan, frekuensi, dominansi, dan indeks nilai penting. Struktur tegakan kabesak di lahan hutan sekunder, padang rumput, dan semak belukar, serta taman menunjukkan bentuk J terbalik, yang menyiratkan bahwa regenerasi pada tiga jenis lahan berjalan baik. Kabesak memiliki hubungan yang signifikan dengan beberapa spesies tanaman, baik tipe negatif maupun positif. Hasil analisis regresi komponen utama menunjukkan bahwa kontribusi faktor tanah mempengaruhi kepadatan populasi kabesak (individu ha -1 ). Variabel tanah yang memiliki efek positif tertinggi terhadap kepadatan kabesak adalah fraksi debu tanah dan fosfor (P), sedangkan yang memiliki efek negatif tertinggi adalah tanah berpasir dan fraksi natrium. Tes ketinggian dengan uji Tukey (α = 0,05) mengungkapkan bahwa 0-300 m dpl., 300-600 m dpl., 600-900 m dpl tidak berbeda satu sama lain, sementara ketinggian> 900 m dpl secara signifikan berbeda dari kelompok lain.

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A silvicultural stand density model to control understory in maritime pine stands

Cited by 19 publications

References 18 publications

Size–Density Trajectory in Regenerated Maritime Pine Stands after Fire

Size–Density Trajectory in Regenerated Maritime Pine Stands after Fire

Generalized Nonlinear Mixed-Effects Individual Tree Crown Ratio Models for Norway Spruce and European Beech

Stand and Site Characteristics of Kabesak (Acacia leucophloea) in Timor Island, East Nusa Tenggara, Indonesia

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