含固定效應(yīng)的多形立地指數(shù)模型構(gòu)建與應(yīng)用研究
發(fā)布時(shí)間：2018-10-29 10:17
【摘要】：立地指數(shù)模型是評(píng)價(jià)森林立地質(zhì)量的核心和關(guān)鍵。鑒于現(xiàn)有的立地質(zhì)量評(píng)價(jià)研究,沒有全面的考慮立地類型和林分類型對(duì)立地質(zhì)量的影響,從而導(dǎo)致同一立地類型、同一樹種在相同的條件下得到不同的生長過程,使得建立的立地質(zhì)量評(píng)價(jià)模型難以推廣、限制了其適用性,且現(xiàn)有的立地質(zhì)量評(píng)價(jià)研究對(duì)天然混交林研究較少。通過研究,以期使建立的立地指數(shù)模型容易推廣、適用性強(qiáng),解決區(qū)域性兼容問題,并嘗試探索解決天然林立地質(zhì)量評(píng)價(jià)問題。本文以湖南省杉木人工林和亞熱帶櫟類天然混交林為研究對(duì)象,利用調(diào)查數(shù)據(jù),從基于樹高-年齡分級(jí)的多形立地指數(shù)模型和基于立地類型聚類的多形立地指數(shù)模型兩方面入手,深入研究了含固定效應(yīng)的多形立地指數(shù)模型在湖南省杉木人工林和亞熱帶櫟類天然混交林上的構(gòu)建與應(yīng)用。主要研究內(nèi)容和結(jié)論如下:(1)通過樹高-年齡分級(jí)構(gòu)建固定效應(yīng)的方法,建立了基于樹高-年齡分級(jí)的杉木人工林多形立地指數(shù)模型。指出齡階間距為5年,樹高分9級(jí),其所得的分級(jí)結(jié)果最佳,與基礎(chǔ)模型相比,將模型的確定系數(shù)從0.79964增至0.95303,大大提高了模型的精度。同時(shí)也驗(yàn)證了樹高-年齡分級(jí)的方法應(yīng)用于人工林立地質(zhì)量評(píng)價(jià)種是正確、可行的。(2)通過立地類型聚類構(gòu)建固定效應(yīng)的方法,建立了基于立地類型聚類的杉木人工林多形立地指數(shù)模型。將606個(gè)樣本中立地因子相同的進(jìn)行組合,劃分為240個(gè)初始立地類型,并將初始立地類型作為固定效應(yīng)加在參數(shù)a上進(jìn)行含固定效應(yīng)的非線性回歸模型模擬,得到240個(gè)初始立地類型所對(duì)應(yīng)的系數(shù)值;用R軟件中k-means聚類,將240個(gè)不同的立地類型聚為12類,合并后的因子水平信息包含合并前的因子水平信息的99%。將各樣本的立地類型轉(zhuǎn)換為對(duì)應(yīng)的類,并將12個(gè)類作為固定效應(yīng)加在基礎(chǔ)模型上進(jìn)行非線性擬合回歸分析,模型的確定系數(shù)R2=0.98811,進(jìn)一步提高了模型的精度,證實(shí)了立地類型聚類構(gòu)建固定效應(yīng)的思維和方法應(yīng)用于人工林立地質(zhì)量評(píng)價(jià)中是具有可行性的。(3)將兩種立地質(zhì)量評(píng)價(jià)方法應(yīng)用于櫟類天然混交林中進(jìn)行探索研究,建立了兩種不同的櫟類天然混交林多形立地指數(shù)模型:1)采用樹高-年齡分級(jí)構(gòu)造固定效應(yīng)建立多形立地指數(shù)模型的方法,建立了櫟類天然林多形立地指數(shù)曲線模型,確定系數(shù)R2= 0.9807,模型精度較高,且建模過程無需添加立地因子,操作簡單。2)采用立地類型聚類構(gòu)造固定效應(yīng)建立多形立地指數(shù)模型的方法,建立了櫟類天然林多形立地指數(shù)曲線模型,確定系數(shù)R2= 0.87584,模型精度較高,且能夠保證同一立地類型、同一樹種在相同的條件下得到幾乎相同的生長過程。3)相對(duì)于同形立地指數(shù)模型無法擬合櫟類天然林生長過程的情況,兩種方法均能適用于櫟類天然林立地質(zhì)量評(píng)價(jià),且建立的模型精度高、適用性強(qiáng),可解決天然林立地質(zhì)量評(píng)價(jià)問題,為天然林立地質(zhì)量評(píng)價(jià)提供了一種新思路和參考方法。(4)研究提出的兩種多形立地指數(shù)模型構(gòu)建方法,既適用于人工林又適用于天然林立地質(zhì)量評(píng)價(jià)。建立的模型適用性強(qiáng),可解決區(qū)域性兼容問題和天然林立地質(zhì)量評(píng)價(jià)問題。含固定效應(yīng)的多形立地指數(shù)模型為我國森林立地質(zhì)量評(píng)價(jià)提供了一種新思路和方法,不僅適用于杉木人工林和櫟類天然混交林,也可借鑒于其它林分類型的立地質(zhì)量評(píng)價(jià)中。
[Abstract]:Site index model is the core and key point of evaluating forest site quality. In view of the existing site quality evaluation research, there is no comprehensive consideration of the influence of site type and forest sub-type on the quality, thus leading to the same site type, and the same tree species are subjected to different growth processes under the same conditions, so that the established site quality evaluation model is difficult to popularize, The applicability of the study was limited, and the existing site quality assessment was less than that of the natural mixed forest. Through the research, the establishment of the site index model is easy to popularize, the applicability is strong, the regional compatibility problem is solved, and the problem of the quality evaluation of the natural forest land is attempted to be solved. Based on the investigation data, this paper starts with the multi-site index model based on tree height-age classification and the multi-site index model based on site type based on the investigation data. In this paper, the construction and application of multi-site index model with fixed effect on the natural mixed forest of Chinese fir plantation and sub-tropical oak forest were studied. The main research contents and conclusions are as follows: (1) The multi-shape site index model of Chinese fir plantation based on tree height-age classification is established by constructing the fixed effect by tree height-age classification. It is pointed out that the age-order spacing is 5 years and the tree high score is 9. The obtained grading results are the best. Compared with the basic model, the determination coefficient of the model is increased from 0. 79964 to 0. 95303, which greatly improves the accuracy of the model. At the same time, it is proved that the method of tree height-age classification is correct and feasible. (2) A multi-shape site index model of Chinese fir plantation based on site type is established by constructing fixed effect by site type poly. combining 606 sample neutral factors into 240 initial site types, adding the initial site type as a fixed effect and a nonlinear regression model containing a fixed effect on the parameter a to obtain the coefficient values corresponding to 240 initial site types; Using the k-means poly in R software, 240 different site types are grouped into 12 classes, and the combined factor level information contains 99% of the factor level information before consolidation. the site conditions of each sample are classified into corresponding classes, and 12 classes are added as a fixed effect to carry out nonlinear fitting regression analysis on the basic model, the determination coefficient R2 of the model is 0.98811, and the accuracy of the model is further improved, It is proved that the method of thinking and method for constructing fixed effect of site type polytype is feasible in the quality evaluation of artificial forest land. (3) the two site quality evaluation methods are applied to the exploration and research of the oak-type natural mixed forest, and two different kinds of natural mixed forest multi-shape site index models are established: 1) a method for establishing a multi-shape site index model by adopting a tree height-age hierarchical structure fixing effect is established; A multi-site index curve model of oak forest is established, and the coefficient R2 = 0.9807, the model precision is high, and the modeling process does not need to add site factors, and the operation is simple. The multi-site index curve model of oak forest is established, and the coefficient R2 = 0.987584, the model precision is high, and the same site type can be ensured. the same tree species are almost the same under the same conditions. 3) the condition that the growth process of the oak forest natural forest cannot be fitted with respect to the homomorphic site index model, both methods can be applied to the quality evaluation of the oak natural forest, and the established model is high in accuracy and strong in applicability, The method can solve the problem of quality evaluation of the natural forest, and provides a new idea and a reference method for the quality evaluation of the natural forest. (4) The construction method of two kinds of site index models proposed in this paper is suitable for the quality evaluation of natural forest. The established model has strong applicability, can solve the regional compatibility problem and the quality evaluation problem of natural forest land. The multi-site index model with fixed effect provides a new idea and method for forest site quality evaluation in China. It is not only suitable for Chinese fir plantation and oak-type natural mixed forest, but also can be used for site quality evaluation of other forest types.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：S757
，
本文編號(hào)：2297409
[Abstract]:Site index model is the core and key point of evaluating forest site quality. In view of the existing site quality evaluation research, there is no comprehensive consideration of the influence of site type and forest sub-type on the quality, thus leading to the same site type, and the same tree species are subjected to different growth processes under the same conditions, so that the established site quality evaluation model is difficult to popularize, The applicability of the study was limited, and the existing site quality assessment was less than that of the natural mixed forest. Through the research, the establishment of the site index model is easy to popularize, the applicability is strong, the regional compatibility problem is solved, and the problem of the quality evaluation of the natural forest land is attempted to be solved. Based on the investigation data, this paper starts with the multi-site index model based on tree height-age classification and the multi-site index model based on site type based on the investigation data. In this paper, the construction and application of multi-site index model with fixed effect on the natural mixed forest of Chinese fir plantation and sub-tropical oak forest were studied. The main research contents and conclusions are as follows: (1) The multi-shape site index model of Chinese fir plantation based on tree height-age classification is established by constructing the fixed effect by tree height-age classification. It is pointed out that the age-order spacing is 5 years and the tree high score is 9. The obtained grading results are the best. Compared with the basic model, the determination coefficient of the model is increased from 0. 79964 to 0. 95303, which greatly improves the accuracy of the model. At the same time, it is proved that the method of tree height-age classification is correct and feasible. (2) A multi-shape site index model of Chinese fir plantation based on site type is established by constructing fixed effect by site type poly. combining 606 sample neutral factors into 240 initial site types, adding the initial site type as a fixed effect and a nonlinear regression model containing a fixed effect on the parameter a to obtain the coefficient values corresponding to 240 initial site types; Using the k-means poly in R software, 240 different site types are grouped into 12 classes, and the combined factor level information contains 99% of the factor level information before consolidation. the site conditions of each sample are classified into corresponding classes, and 12 classes are added as a fixed effect to carry out nonlinear fitting regression analysis on the basic model, the determination coefficient R2 of the model is 0.98811, and the accuracy of the model is further improved, It is proved that the method of thinking and method for constructing fixed effect of site type polytype is feasible in the quality evaluation of artificial forest land. (3) the two site quality evaluation methods are applied to the exploration and research of the oak-type natural mixed forest, and two different kinds of natural mixed forest multi-shape site index models are established: 1) a method for establishing a multi-shape site index model by adopting a tree height-age hierarchical structure fixing effect is established; A multi-site index curve model of oak forest is established, and the coefficient R2 = 0.9807, the model precision is high, and the modeling process does not need to add site factors, and the operation is simple. The multi-site index curve model of oak forest is established, and the coefficient R2 = 0.987584, the model precision is high, and the same site type can be ensured. the same tree species are almost the same under the same conditions. 3) the condition that the growth process of the oak forest natural forest cannot be fitted with respect to the homomorphic site index model, both methods can be applied to the quality evaluation of the oak natural forest, and the established model is high in accuracy and strong in applicability, The method can solve the problem of quality evaluation of the natural forest, and provides a new idea and a reference method for the quality evaluation of the natural forest. (4) The construction method of two kinds of site index models proposed in this paper is suitable for the quality evaluation of natural forest. The established model has strong applicability, can solve the regional compatibility problem and the quality evaluation problem of natural forest land. The multi-site index model with fixed effect provides a new idea and method for forest site quality evaluation in China. It is not only suitable for Chinese fir plantation and oak-type natural mixed forest, but also can be used for site quality evaluation of other forest types.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：S757
，
本文編號(hào)：2297409
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