DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 3-4/2010 str. 48 <-- 48 --> PDF |
Š. Pezdevšek Malovrh, L. Zadnik Stirn, J. Krč: INFLUENCE OF OWNERSHIPAND PROPERTYSTRUCTURE ... Šumarski list br. 3–4, CXXXIV (2010), 139-149 size and fragmentation of the forest property, form of ownership and number of co-owners.These variables can 2 either be continuous, discrete or attributive.The . test was used in order to find out whether there is a relationship between pairs of variables. Statistically significant relationship between two variables was defined where p 2 value was less than 0.05.The . tests were performed by using theSPSS for Windows 16.0computer package. Willingness of private forest owners for cooperation regarding the age of forest owners and the ownership and property structure was performed by the nominal logistic regression method (Backhaus,2004,Grimm et. al, 2002,Košmelj,2001a,Košmelj,2001b, Ho- s mer, Lemeshow, 2000, Albright et. al., 2000, Norman,2000), by means of theBackward stepwise algorithm (Field,2009) of theSPSS for Windows 16.0 software package. The nominal logistic regression is a generalised version of logistic regression. Logistic regression belongs to the generalised linear models, which are used for the prediction of binary dependant variables (“yes”/“no”). In our case, however, the dependant variable has three values – associated, willing to cooperate and unwilling to cooperate.This kind of statistical model is referred to as nominal logistic regression model. (Košmelj, Vadnal,2003).The last category of the independent variable was chosen to represent the reference cate gory.The estimation of the parameters in logistic re gression is based on the method of maximum likelihood. TheWald testwas used to establish the statistical significance of the correlation between the dependant variable and the independent variables.The uncharacteristicWald test enables the exclusion of insignificant variables from the model, thus ridding the model of unnecessary, disturbing variables. The logistic regression method was chosen due to the fact that it involves fewer statistical requirements than alternative methods, such as discriminant analysis, pro- bit analysis, etc. Unlike the aforementioned ana lyses, the nominal logistic regression is not based on the assumption of linear correlation between the independent and the dependant variable nor the assumption of homoscedasticity. However, logistic regression has an inconvenience, namely, the multicollinearity (Poje, 2003). Multicollinearity refers to a situation in which independent variables in a regression model are a linear combination of other independent variables. In logistic regression, to avoid multicollinearity, none of the independent variables of a multiple model may therefore represent a linear combination of other independent variables (Jesenko, 2007).The independent variables which are a linear combination of other independent variables are thus to be excluded from the model. RESULTS AND DISCUSSION – Rezultati i rasprava Basic information about sample- private forest owner Osnovni podaci o anketiranima šumoposjednicima The sample represents 322 forest owners, 75.8 % of (68.9 %) live in rural area, a hamlet or a small village of whom are male and 24.2 % are female.The average age up to 500 inhabitants with neither shop nor post office, of the respondents is 54 years and the average level of who generally belong to a village local community education is completed primary education(31.7 %) or (82.9 %). More than half of the respondents (58.9 %) vo cational school (32.6 %). The majority of respondents consider their economic status to be average. General data relating to property conditions – Opći podaci o strukturi šumoposjeda The mean area of forest ho lding of the respondents is 16.7 ha.The size of the smallest forest property is 0.1 ha, while the biggest forest property extends up to 150 ha.The respondents were classified depending on the size of their forest property into categories referred to as stratums.The stratums and the shares of the respondents per stratum are given inTable 1. Table 1 shows that approximately the same number of forest owners from all stratumsparticipated inthe sur- Table 1.Size of forest property (stratum) Tablica 1.Veličina posjeda (grupe) Stratum (ha)– Grupe (ha) Up to 0.99 Do 0,99 1 to 4.99 1 do 4,99 5 to 9.99 5 do 9,99 10 to 29.99 10 do 29,99 Over 30 Više od 30 n1990649158 %5.928.019.928.318.0 vey. The exception is the first stratum (up to 0.99 ha) with the share of only 5.9 %. Such small number of the respondents from the first stratum is due to several causes: some owners refused to take part in the survey or were not even aware that they own a forest, the address of some owners could not be found or it was impossible for us to contact them or they are deceased.The refusal of the owners of forest properties smaller than 1 ha to participate in the survey shows their inactiveness, lack of interest or negative attitude towards foresters and even the forest itself. The respondents, generally know how many separate plots of forest they possess. Only 2.5 % of the respondents could not answer this question and were therefore excluded from the analyses relating to the |