tree canopies
Recently Published Documents


TOTAL DOCUMENTS

314
(FIVE YEARS 69)

H-INDEX

34
(FIVE YEARS 4)

Author(s):  
Connel Ching'anda ◽  
Joseph Atehnkeng ◽  
Ranajit Bandyopadhyay ◽  
Kenneth Callicott ◽  
Marc J Orbach ◽  
...  

Aspergillus flavus infects a wide range of crops, including pistachios, and subsequent aflatoxin contamination results in significant economic losses. Application of biocontrol products based on non-aflatoxigenic (atoxigenic) strains of A. flavus is one of the most effective tactics for controlling aflatoxins in crops. Both risk of aflatoxin contamination and effectiveness of biocontrol are influenced by the extent to which A. flavus spores move into pistachio tree canopies during periods of nut development. Thus, the purpose of this study was to evaluate spatial and temporal population dynamics of A. flavus, including the applied biocontrol strain AF36, in canopies of pistachio orchards in Arizona. Propagule densities of A. flavus were quantified on leaf samples collected from lower, middle, and upper canopies from spring through harvest in 2018 and 2019. Aspergillus flavus propagule densities peaked during periods of high temperature and rainfall in 2018 (up to 600 CFU/g) and 2019 (up to 23 CFU/g), which coincided with nut development and maturation. The applied biocontrol strain AF36 was detected at all canopy heights, but overall propagule densities were greater in the upper and middle canopy (mean = 70 CFU/g) compared to the lower canopy (mean = 47 CFU/g). Results suggest June to August is the period during which A. flavus inoculum increases in Arizona pistachio orchards, and to most effectively displace aflatoxin-producing fungi in tree canopies, biocontrol applications should precede this period. In addition, this study demonstrates that soil-applied biocontrol strains can successfully disperse throughout the canopies of commercial tree nut orchards.


2022 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Suliman Gargoum ◽  
Lloyd Karsten ◽  
Karim El-Basyouny ◽  
Xinyu Chen

Fatalities and serious injuries still represent a significant portion of run-off-the-road (ROR) collisions on highways in North America. In order to address this issue and design safer and more forgiving roadside areas, more empirical evidence is required to understand the association between roadside elements and safety. The inability to gather that evidence has been attributed in many cases to limitations in data collection and data fusion capabilities. To help overcome such issues, this paper proposes using LiDAR datasets to extract the information required to analyze factors contributing to the severity of ROR collisions on a localized collision level. Specifically, the paper proposes a new method for extracting pole-like objects and tree canopies. Information about other roadside assets, including signposts, alignment attributes, and side slopes is also extracted from the LiDAR scans in a fully automated manner. The extracted information is then attached to individual collisions to perform a localized assessment. Logistic regression is then used to explore links between the extracted features and the severity of fixed-object collisions. The analysis is conducted on 80 km of roads from 10 different highways in Alberta, Canada. The results show that roadside attributes vary significantly for the different collisions along the 80 km analyzed, indicating the importance of utilizing LiDAR to extract such features on a disaggregate collision level. The regression results show that the steepness of side slopes and the offset of roadside objects had the most significant impacts on the severity of fixed-object collisions.


2021 ◽  
Vol 14 (2) ◽  
pp. 116-125
Author(s):  
Dahlan Dahlan ◽  
Iqbar Iqbar ◽  
Eka Puspita Sari ◽  
Nizamuddin Nizamuddin

Abstrak. Sempadan sungai merupakan kawasan penyangga antara ekosistem perairan (sungai) dan daratan. Sungai Krueng Lamnyong terletak di Kota Banda Aceh dan Kabupaten Aceh Besar yang merupakan daerah hilir dari sungai Krueng Aceh. Sempadan sungai Krueng Lamnyong telah dimanfaatkan oleh berbagai pihak untuk berbagai peruntukan. Penelitian ini bertujuan untuk mengevaluasi kesesuaian peruntukan lahan sempadan sungai Krueng Lamnyong berdasarkan peraturan perundang-undangan. Identifikasi serta evaluasi peruntukan lahan di sempadan sungai Krueng Lamnyong menggunakan perangkat lunak Sistem Informasi Geografis (SIG). Hasil penelitian menunjukkan bahwa penggunaan sempadan sungai Krueng Lamnyong diperoleh 10 jenis penggunaan lahan. Penggunaan sempadan sungai Krueng Lamnyong yang teridentifikasi sesuai dengan peruntukan yaitu sebesar 110,91 Ha atau 68,13% yang terdiri dari irigasi, jalan, sawah, rerumputan, tanaman palawija dan tanah kosong. Penggunaan yang tidak sesuai peruntukan sebesar 51,88 Ha atau 31,87% yang terdiri dari ruang terbangun, kebun, vegetasi mangrove dan kanopi pohon.Evaluation of Land Use Suitability in Aceh Province's Krueng Lamnyong River BorderAbstract. The river border is a buffer area between aquatic ecosystems (rivers) and land. The Krueng Lamnyong River is located in Banda Aceh City and Aceh Besar District which is the downstream area of the Krueng Aceh river. The Krueng Lamnyong river border has been used by various parties for various purposes.  This study aims to evaluate the suitability of the land use of the Krueng Lamnyong river border based on the legislation. Identification and evaluation of land use in the Krueng Lamnyong river border using Geographic Information System (GIS) software. The results showed that the use of the Krueng Lamnyong river border obtain 10 types of land use. The use of the Krueng Lamnyong river border identified according to its designation is 110.91 Ha or 68.13% consisting of irrigation, roads, rice fields, grass, crops, and vacant land. The use that is not in accordance with the designation is 51.88 Ha or 31.87% consisting of build space, gardens, mangrove vegetation, and tree canopies.


2021 ◽  
pp. 0739456X2110536
Author(s):  
C. J. Gabbe ◽  
Gregory Pierce ◽  
Emily Petermann ◽  
Ally Marecek

Heat is the deadliest weather-related hazard in the United States. This paper studies municipal heat adaptation using survey and planning data from California. We first analyze the characteristics of municipalities that innovate. Cities with heat-related policies have greater degrees of projected extreme heat, leadership support, environmental justice planning, and smaller Hispanic population shares. We then assess specific policy innovations of six large cities by plan type. Some strategies, including expanding tree canopies, have been widely adopted while others, such as cool walls, are rarely included. Findings suggest that planners can—and should—play a central role in heat adaptation planning.


2021 ◽  
pp. 101465
Author(s):  
José Augusto Correa Martins ◽  
Geazy Menezes ◽  
Wesley Gonçalves ◽  
Diego André Sant’Ana ◽  
Lucas Prado Osco ◽  
...  

2021 ◽  
Vol 13 (19) ◽  
pp. 3919
Author(s):  
Jiawei Mo ◽  
Yubin Lan ◽  
Dongzi Yang ◽  
Fei Wen ◽  
Hongbin Qiu ◽  
...  

Instance segmentation of fruit tree canopies from images acquired by unmanned aerial vehicles (UAVs) is of significance for the precise management of orchards. Although deep learning methods have been widely used in the fields of feature extraction and classification, there are still phenomena of complex data and strong dependence on software performances. This paper proposes a deep learning-based instance segmentation method of litchi trees, which has a simple structure and lower requirements for data form. Considering that deep learning models require a large amount of training data, a labor-friendly semi-auto method for image annotation is introduced. The introduction of this method allows for a significant improvement in the efficiency of data pre-processing. Facing the high requirement of a deep learning method for computing resources, a partition-based method is presented for the segmentation of high-resolution digital orthophoto maps (DOMs). Citrus data is added to the training set to alleviate the lack of diversity of the original litchi dataset. The average precision (AP) is selected to evaluate the metric of the proposed model. The results show that with the help of training with the litchi-citrus datasets, the best AP on the test set reaches 96.25%.


Mathematics ◽  
2021 ◽  
Vol 9 (19) ◽  
pp. 2431
Author(s):  
Carlos E. Villarreal-Olavarrieta ◽  
Néstor García-Chan ◽  
Miguel E. Vázquez-Méndez

Heat and water transport modeling is a widely explored topic in micro-meteorology, agriculture, and forestry. One of the most popular models is the Simultaneous Heat and Water (SHAW) model, which includes partial differential equations (PDEs) for air-soil temperature and humidity, but with a priori discretized PDE for the foliage temperature in each canopy layer; it is solved using the finite difference method and the canopy shape is defined as a simple rule of proportionality of total quantities such as the total leaf area index. This work proposes a novel canopy shape characterization based on Weibull distribution, providing a continuous vertical shape function capable of fitting any tree species. This allows formulating a fully continuous SHAW-derived model, which is numerically solved by a finite element approach of P1 Lagrange type. For this novel approach, several numerical experiments were carried out to understand how the shape of well distinguishable canopies influences heat and water transport.


2021 ◽  
Author(s):  
Mercedes Ibañez ◽  
Salvador Aljazairi ◽  
María José Leiva ◽  
Roland A. Werner ◽  
Jaleh Ghashghaie ◽  
...  

Abstract Purpose: Mediterranean wood pastures are the largest agroforestry system in Europe. Traditional silvo-pastoral uses shaped these systems into a mosaic of trees and open grassland. However, little is known about how this structure may influence ecosystem carbon (C) and nitrogen (N) dynamics, considering different canopy types and interactions with the herbaceous layer.Aims: To unravel the canopy effect on C and N dynamics (1) under representative canopy types, including traditional Quercus stands and Pinus pinea L. plantations; and (2) in interaction with the herbaceous plant functional types (PFT).Methods: We analysed C and N content and the isotopic natural abundance on soil and plant materials at the open grassland and under the different tree canopies.Results: Under the canopy, soil C and N content, and N availability for the herbaceous layer increased. The canopy effect performed differences between Quercus and P. pinea plots, as detected on the belowground biomass C content. Also, the canopy effect was more pronounced with increasing environmental constraints, highlighting the relevance of trees in more restrictive environments. PFT ecophysiological characteristics interacted with tree canopies, as reflected the enhanced efficiency taking-up N, and/or exploiting symbiotic N of grasses, which was probably one of the causes of their dominancy under the canopy, at higher N availability.Conclusion: Changes in the tree coverage and tree species will significantly change ecosystem C and N storage and cycling. Therefore, it is highly advisable to preserve a balance between trees and open grassland, and traditional Quercus stands, to keep ecosystem services provisioning.


Author(s):  
Phillip L. Martin ◽  
William King ◽  
Terrence H Bell ◽  
Kari Peter

Bitter rot is a disease of apple caused by fungi in the genus Colletotrichum. Management begins with removal of infected twigs and fruits from tree canopies to reduce overwintering inoculum. Infected apples are usually tossed to the orchard floor, which is generally managed as herbicide-treated weed-free tree rows, separated by grass drive rows. We monitored decay rates and succession of fungi of apples with bitter rot in tree canopies, and on the soil surface in tree rows, grass drive rows, and nearby diverse plant communities. We hypothesized that decay would occur most rapidly within diverse plant communities, which would provide a more diverse array of potential fungal decomposers. Apples in tree canopies became dry and mummified and had more Colletotrichum gene marker copies the following growing season than did apples on the soil surface. Of the soil surface samples, those in grass drive rows and diverse plant communities had higher moisture, faster decay rates, and sharper decreases in Colletotrichum gene marker copies than apples in tree rows. Fungal composition across all decaying apples was dominated by yeasts, with higher genus-level richness, diversity, and evenness in apples from tree canopies than those on the soil surface. In soil surface apples, we observed clear successional waves of Pichia, Kregervanrija, and [Candida] yeasts, with similar but distinctly diverging fungal composition. Our results show that orchard floor management can influence fungal succession in apples with bitter rot, but suggests that bitter rot management should primarily focus on removing infected apples from tree canopies.


Sign in / Sign up

Export Citation Format

Share Document