• Sumed Gajare asked a question:
    How can we measure bulk density of a different types of forest soil?

    Thanks in advance for your replies.

  • Sean C Thomas added an answer:
    Which criteria should be considered when buying a fish-eye lens for the measurement of leaf area index (LAI)?

    I have a planning on buying a fish-eye lens, and therefore, I need to know some criteria before buying. Most Regards, Moein

    Sean C Thomas · University of Toronto

    An additional critical point is that the fisheye lens should be equalangular (a displacement along the image radii at any distance from the center to the edge should correspond to the constant angular displacement).  Some analysis software will allow you to adjust for non-equalangular lenses, but mostly this property is assumed.

  • Md. Siddiqur Rahman added an answer:
    How can the contribution of the forestry sector of any country be measured towards GDP calculation accurately?

    Forestry sector contributing toward national GDP has always been underestimated in the tropics due to many reasons. Ranging from environmental to educational, and widening between infrastructural and methodological approaches adopted; how best forest assests and liabilities could be accounted using GAAP (Generally Accepted Accounting Principles)?

    Md. Siddiqur Rahman · University of Chittagong

    that's what I was talking about...

  • Jean O'Dwyer added an answer:
    What is the best Life Cycle Assessment software in terms of cost:benefit?

    I am involved in a Forestry themed project and am assessing cascade use of harvested wood products and would like to employ LCA (though it is not the whole focus). However, the software is quite expensive for the big names i.e. SimaPro, GaBi, etc.

    Has anyone used OpenLCA? How does this compare to the paid platforms in terms of ease of use, accuracy, defensibly etc. 

    Any help would be greatly appreciated.

    Jean O'Dwyer · University of Limerick

    Thank you all for your valuable insight. You have all been a great help.

  • Xiping Zhao added an answer:
    Which statistical analysis should I use to analyse my data?

    I want to compare Specific Leaf Area (SLA), Leaf Area Index (LAI) and biomass allocation of different tree components in different light condition (light gradient) for three species. I have three light level and also have the amount of light (%) for each tree individual. There are three replication for each light level and there are three trees in each replication. I want to know the impact of light and species on my above variables. Moreover, trees are not the same size and size affects the results. I want size to be ignored. only impact of the light and species.

    Thanks in advanced

    Xiping Zhao · Henan University of Science and Technology

    hi, Ardalan.The size affects the results. So,you can ignore that. I think  You can use a mixed effects model to analyze your data with tree size being a covariant.

  • Ahmad Moghaddam gheshlagh added an answer:
    Which method on gene transfer on forest species is better?


    For improve the velocity of the plant growth, on arid forest species, which biblography o references are recommending? Regards

    Ahmad Moghaddam gheshlagh · Universidad Autónoma de Sinaloa

    Thanks Alot friends for your articles that send to me, best for you. i will check them

  • Napoleon Ono Imaah added an answer:
    What are the opportunities and challenges in adopting ecosystem-based approach for managing degraded ecosystems in semiarid landscapes (Ghana)?

    Role of local knowledge practices.

    Climate change and variability impacts.

    Napoleon Ono Imaah · Rivers State University of Science and Technology

    Various opportunities and challenges emanate when people apply appropriate ecosystem-based management approach to semiarid, arid or any other  types of environments that might be deficient of desired but deficient of qualitative and quantitative climatological elements. Arid and semiarid environment lack sufficient quantity of water, which might also be deficient in quality in the atmosphere and in the ground. Situation. This situation leads to scanty or stunted plant of growth.in poor, scorched soils.

    The opportunities to manage the ecosystem-based landscapes well, is like nurturing sick people back to health; using both affordable local herbs and foods. Opportunities in management of the ecosystem's water supply systems in order to improve on the quality of the soil and increase plant growth are available. The opportunity to introduce irrigation could follow improved water supply due to good ecosystem-based approach in the management of resources and landscapes. Many opportunities will manifest to develop: Agriculture, agronomy and horticulture. With sufficient efficiently managed ecosystem-based landscapes, there will emerge aquaculture and fish farming. The dry hot semiarid environment is very good for a quick turnover in fish farming. Opportunities also abound for the establishment of agro-allied industries. Thus, the opportunities to improve the quality of life of the people within a well managed ecosystem-based landscapes will multiply.

    Challenges follow opportunities in the semiarid and arid environments as they do in all other circumstances of life. The challenges in the arid and semiarid environments are similar to squeezing water from stone. The challenge of sustainability of attained results is as tough as riding on the back of a tiger: if sustainability stops, the ecosystem dies; just as the rider dies if the rider stops riding the tiger.

    The inspirational success of Israel in managing their ecosystem and eventually turning the hitherto barren, fruitless land into a fruitful “land flowing with milk and honey” proves that opportunities are possible in the face of otherwise daunting challenges. Another emergent ecosystem management success stories  if happening in the arid and semiarid environments on mountains of South America. The people now affordable technology harvest dew from their ecosystem and manage it successfully for drinking and watering of their beasts and plants. Therefore, I believe that your research will find many opportunities amid the challenges.

  • Neil Andrew White added an answer:
    Is it important to carry out a research to determine fruit yield of Mangos? Interpret results to needy communities on yield of fruit trees planted.

    Departmental Orchards in Northern Namibia.

    Determining fruit yield of Mangos.

    Neil Andrew White · Queensland Government

    This is important in all societies. Growers need access to the affect of management on fruit yield regardless of their socio-economic status. Muhammad's answer is interesting to me as we are investigating a range of "radical" approaches to increasing yield per ha in mango, macadamia and avocado, including training, high density and dwarfing rootstocks.

  • Peter Salonius added an answer:
    To integrate or to segregate: what are the best approaches for the conservation of forest biodiversity?

    In Europe, but also in other parts of the world, there are two different main approaches for forest biodiversity conservation on a larger scale (landscape, regional, national scale). The segregative approach separates large areas for nature reserves without any management from other areas with intensive forest management for economic purposes. The integrative approach tries to combine nature conservation and economic management by including the provision of e.g. structural heterogeneity, species mixtures and DWD in a more extensive, so-called 'close-to-nature' forestry.

    I wonder if there are studies and scientific results regarding the efficiency and cost-benefit ratios of both approaches in comparision. I would be glad if you could provide me with any information on this for any part of the world.

    There is a nice publication of the European Forest Institute (EFI) providing more insights in the integrative approach (see link).

    Thanks a lot in advance.

    Best regards,

    Peter Salonius · Natural Resources Canada, Retired

    Subject: Subsidy alternatives to change forest management 
     you may be interested to read:
    'Shifting regeneration subsidies - A route to saving money and restoring temperate forest
    starting on Page 5 and continuing on Page 7........ at:

    Peter Salonius

  • Christoph Leibing added an answer:
    In short rotation forestry, which density per hectare provides the greatest amount of biomass in 5 years for poplar sp.?

    For short rotation forestry, which density per hectare provides the greatest amount of biomass in 5 years for poplar sp.?

    Christoph Leibing · University of Hamburg


    modern 5 a rotation SRC in Europe with max yield in bdt/ha is 1660 trees per ha, usually in 3x2m spacing. The genotypes used are usually P. euroamericana clones. Would be great to receive a copy of your article once you are published lulian.



  • Emily Gilbert added an answer:
    Can a strip sampling method be as effective as line transect sampling for tree inventory?

    I wanted to know if a strip sampling method can be as effective as line transect sampling for tree inventory especially in representing a 0.1 ha of a forest area.

    Emily Gilbert · Universiti Malaysia Sabah (UMS)

  • Farhad Khorsandi added an answer:
    Why is acacia sp. more popular for paper production than kenaf sp?
    As I made some revision on this species, kenaf is quite a multipurpose species. So I wonder why this species is not really well known among the people.
    Farhad Khorsandi · Islamic Azad University

    Excellent answers by Frank and Tarig. I may also add that in general Acacia species require less water, which is an important factor in dry arid regions.

  • Yasser El-Nahhal added an answer:
    What is a suitable method to determine rate of combustion of tropical peat?

    to compare tropical peat by depth

    Yasser El-Nahhal · Islamic University of Gaza

    You can do thes by collecting CO2 production in due time through passing CO2 in solution containing Ca(OH)2. then you can determine the amount of CaCO3 produced over time. then drowing the relation ship between CaCO3 and time > this may give you a linear relationship. the slope of the line would br the the rate you need.

    Best regards


  • Carl W. Mize added an answer:
    How far apart do forest inventory plots need to be apart to be considered a systematic sample?

    I am helping foresters in the tropical forests of the Yucatan Peninsula with the analysis of inventory data.  They use strip plots but often have relatively few in an inventory so their t value for a confidence interval is large and the confidence interval for volume is large also. They are considering changing to systematically arranged fixed area plots and would like to keep them relatively close. That creates the question - how close?

    Carl W. Mize · Iowa State University

    chip.  100 m might be doable.  they could enlarge their plots.  variability is very high, at least species.  in 2.5 ha of forest there are about 100 species of trees. the forests are relatively dry (for tropical forests) with a history of usage for slash and burn that goes back 2000+ years plus hurricanes and the odd large fires that often follow hurricanes.

  • Iulian Danila added an answer:
    Any suggestions on seedling, cuttings or rods for short rotation forestry (SRF)?

    what is the most productive type of material for reproduction in biomass production? generally is used for poplar SRF - cuttings, seedlings and sits (rods). Thanks.

    Iulian Danila · Stefan cel Mare University of Suceava

    in Romania we have some different results about all type of reproduction material, so for different density (1333 - 2667 trees/ha), and different cycle we obtained that seedlings and rods (sits) are higher than cuttings of Max 4.

  • Megan Foley added an answer:
    How to estimate Leaf Area Index/Canopy Area Index (LAI/CAI) of individial trees by using of hemispherical photos?

    Hello all,

    I am about to estimate leaf area index (in the leafed period) and canopy area index (in the leafless period) of some sparse oak forest stands. Since these forest are very sparse in density, we should consider, first, some individual trees to estimate and generalize these individual estimates to whole stands then. So, we need to estimate LAI and CAI of single trees. Meanwhile, change detection of aforementioned indexes in various phenological stages is the reason for using hemispherical photos.

    Best wishes,


    Megan Foley · Portland State University

    Here's a paper you might find useful: "Validation of LAI and FPAR products" (http://data.auscover.org.au/xwiki/bin/view/Good+Practice+Handbook/LAIFPARValidation?xpage=office&attachment=LAIandFPAR_Validation_For_AusCover_Greenbook_v13.docx)

    And here's one of the instruments discussed that is good for measuring LAI in the field: http://www.cid-inc.com/products/leaf-area-lai/plant-canopy-imager 

    Hope that helps!

  • Mugunthan Perumal added an answer:
    What is the best transplanting period for Shorea macrophylla seedlings after nursery stage to the field?

    Reforestation, Soil Fertility, Ecology 

    Mugunthan Perumal · University Malaysia Sarawak

    Thank you for your suggestions, Afi Nursafingi. 

  • Sean C Thomas added an answer:
    What is a standard method to calculate carbon sequestration by trees?

    We have counted trees for carbon sequestration of our university. I wish to know the standard method to calculate carbon sequestered by these trees.

    Sean C Thomas · University of Toronto

    As mentioned the most common approach for forest C inventory is to utilize allometric equations for biomass, and then to assume that woody tissue is 50% carbon.  This latter assumption is, however, incorrect - see publications below for guidance.

  • Cherine Akkari added an answer:
    Are there records on harmful effects of Puma´s commercial urine used in wild environments?

    Our research permit has been observed because we propose the use of commercial urine from pumas as a scent attractant.

    Cherine Akkari · Université de Montréal

    Hello Antonio!

    Does your research only include the urine of Puma or does it extend to Puma's feces?

    I was able to find this study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4132518/

    Also, see the attached file

  • Vladimirs Biziks added an answer:
    Can you comment on the indirect estimation of wood density and its importance in forestry?
    See above
    Vladimirs Biziks · Georg-August-Universität Göttingen


    Dear Uthappa,

    Other possibility is to apply micro-drilling technique, according the force during the drill it will be possible to estimate the density......Just check the micro-drilling....

    Best regards


  • Klaus Gadow added an answer:
    What is the best analysis to calculate the growth rate for this group of a tree area for ten years?

    If you have the area of certain trees for successive ten years, what is the best analysis to calculate the growth rate for this group? And if you have the weather data for the area, what are the analysis you use?

    Klaus Gadow · Beijing Forestry University, China; University of Stellenbosch South Africa; University Göttingen Germany

    You have two crown surface areas. The difference gives the increase in crown surface areas for each tree. A first approach would be to plot the increase in crown surface area over initial crown surface area and to fit a model. My guess is that eventually you want to estimate the volume (or biomass) growth rate of each tree ? In that case you would need to estimate the relationship between tree crown surface area and tree diameter from a sample of ground measurements. Tree diameter will enable you to estimate tree volume (and biomass) using standard techniques. 

  • Eugen Iordache added an answer:
    What is a proportion of sanitary fellings in forests of European countries?

    Regarding disturbances in European forests, annual average of about 8.1% of the total felling (i.e. 35 million m3 of wood) was damaged by disturbances in Europe over the period 1950–2000 (Schelhaas et al. 2003, Glob Change Biol 9: 1620–1633).

    In Slovakia, annual average of sanitary felling is 48% of total fellings over past 28 years (1986–2013).

    UPDATE (Dec 2, 2014): Over the period 1950–2000, ca. 75 million m3 of wood was damaged (and felled) only in Slovakia. Thus a pan-European estimate by Schelhaas et al. has to be considerably underestimated...

    What about other European countries? What is the percentage (volume) of total fellings being damaged by disturbances?

    Eugen Iordache · Universitatea Transilvania Brasov

    In Romania, in 2013 was harvested 3,6 mil cubic meters( incidental fellings )from  the total 9,582 mil. cubic meters .(37,57%)

  • Miguel Ángel Sarmiento added an answer:
    Is anybody working on non wood products derived from prosopis?

    I´m working on develop non wood products derived from prosopis in Argentina with little farmers in native prosopis forests   

    Miguel Ángel Sarmiento · Universidad Nacional de Santiago del Estero

    Thanks Bernhard, have already provided training to villagers in areas where markets carob flour will develop. Your documents were very helpful. Thanks again. Miguel

  • Sean Haughian added an answer:
    How can i measure topographic mask in a hemispherical photograph?

    I have some hemispherical photograph from forest canopy. the study site has slope and is tilted. I used Gap Light Analyzer 2 for analyses the photographs but in the Calculation Report, the %mask area is too low (~ 0), while i can see topographic mask in the photos. so why? and what is wrong with me?

    Sean Haughian · University of New Brunswick

    Good point about the sky area / mask area division - I must have mis-remembered, as I think you're correct on your interpretation.

  • Francois Libois added an answer:
    What might be the broader strategies to tackle deforestation and forest degradation in case of developing countries like Nepal?

    Currently, Nepal is in transition and developing several types of strategies such as Forestry Strategy for coming 10 years, Terai Arc Landscape Strategy covering from Bagmati River to east to Makakali in the west. Further, REDD Cell has proposed to develop REDD strategy for Nepal. In this context, one of the major issues is deforestation and forest degradation in Nepal. So, how can we go ahead to tackle this issues seriously, so that we can devise the further strategies to tackle the issues? 

    Francois Libois · University of Namur

    Considering the number of Community Forest User Groups in Nepal, we should hope that they are effective to protect forest. We're currently working on that. Up to know, from household survey data, it is clear that population growth and livestock rearing increase pressure on forest. In the Indian Himalayas, a study shows that relatively small LPG subsidies might help to reduce deforestation. It's not sure that it is fully applicable in Nepal since many villages are quite remote. Delivery of LPG as a substitute for firewood as main cooking fuel might be difficult.

    The first link points at a survey of different studies on forestry in the Himalayas, the second one to a more policy oriented paper.

  • Michael Issigonis added an answer:
    Does anybody study "Effects of Hydropower plant (River type) on water quality" at present?

    I have been working and gathering data about this topic related to water quality parameters like DO, TDS, pH, Salnity etc.  for 12 months in one watershed. I came across very few studies on this subject. So, please contribute and expand to this subject with your comments...

    Michael Issigonis · Brandon University

    Reports about water quality after flooding for hydroelectric power generation may not become public or maybe are produced, but are suppressed / hidden from the public. You should be suspicious of mercury contamination in the water which will pass on to fish and humans if they eat the fish. If vegetation/forest was present before the flooding, then there will be emissions of carbon dioxide and methane, so it will not be a "green" energy operation.

  • Satish Kumar Sinha added an answer:
    Do you know a free dendrochronology software?

    We have about 100 disks with diameter from 20 cm to 1.2 meter. We want to measure tree ring width for growth analyzes. We dont have access to lintab, so we are searching for a free software that accept importing scanned images of disks. Since we want to publish our results in a scientific journal, we would like to use a scientifically valid one.

    Satish Kumar Sinha · Navsari Agricultural University

    You just measure the ring-width by live measurement or interactive measurement software or even by scale also and put the value in excel sheet then run  suitable program of freely avialable software DPL and convert it into dacadal basis and then run COFECHA program. In this way You can proceed for dendrochronological research. In my knowledge there is no any free software avialable on internet  that can measure ring-width from scanned images.

  • Marina Zharikova added an answer:
    What fire dynamic model is the most convenient for programming?

    Let me describe my task in short.

    I've created the electronic map of forestry, which includes a set of objects (polygons) of different nature, such as forest plants, roads, lakes etc. Each object is homogeneous. I have to write a program for mapping the dynamic of fire contour on the map. I’m going to use Rothermel’s model, because I have all input data for this model. But this model is good for homogeneous terrain, but my terrain is heterogeneous. I’m looking for the information, how Rothermel’s model can be adjusted to solve my task. Can anyone help me with the information on this question? Maybe there are other models, appropriate for programming... I would be grateful for any help.

    Marina Zharikova · Kherson National Technical University, Kherson, the Ukraine

    Hengky, thank you very much for your help. Very interesting papers, and useful for me.

    I'm developing web-oriented geoinformation system for protection against forest fires. I needed a mathematical model of forest fire dynamic, which I could program and include into my system for visual representation of fire behavior on a map of forestry. I can't use statistical mathematical methods, because I don't have enough data for them.  So, I dwelt on the Rothermel model.

  • Victor L. Barradas added an answer:
    How to measure stemflow of coppice stands such as Quercus sp?

    As we know, coppice species like Quercus sp create several stems per tree making them somewhat hard to estimate their hydrological processes accurately. Does somebody have any ideas as to how to do it?

    Take a look at attached file to see a coppice tree.

    Victor L. Barradas · Universidad Nacional Autónoma de México


    The throughfall contribution to nutrient dynamics depends on the characteristics of the forest or the concerned ecosystems o agricultural or any system. It is not so easy to know about this contribution until measure it. Measurement is relatively easy to make, since it is possible to take samples from the collected water from the throughfall and perform chemical analyzes of the nutrient in question.

  • Xiongqing Zhang added an answer:
    How to calculate nonlinear seemingly unrelated regression (NSUR)?

    Parresol 1999 and Parresol 2001 pointed out that biomass equations should be additive.  He introduced two types of additive biomass equations: weighted seemingly unrelated regression (SUR) and nonlinear seemingly unrelated regression (NSUR). Although, there are some examples in the articles, but the whole procedure remained unclear for use. SUR can be calculated using systemfit  r package. But I don't know how to calculate NSUR. Can I define the formula in r codes as nonlinear so I can calculate NSUR?

    Xiongqing Zhang · Chinese Academy of Forestry

    You can use proc model in SAS

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