Monitoring the effects of stand thinning on microclimates is an integral part of any thinning experiment. It is through its modifications of microclimates that thinning alters important ecological processes. An efficient analysis of microclimate-monitoring data should address both the effects of thinning regimes on, and the temporal response trends of, microclimates. Probably because of the difficulties in modeling temporal trends parametrically, an examination of the existing literature on thinning showed that only a few studies have attempted to address the second aspect. We propose the use of semiparametric smoothing splines to analyze monitoring data from thinning experiments. First, the concept of a smoothing spline is briefly described. We then provide an example in which semiparametric mixedeffects smoothing-spline models were used to analyze microclimate-monitoring data from a thinning experiment. The proposed approach not only successfully detected the effects of thinning, but also revealed interesting temporal trends. For each of the microclimatic variables, we also compared the performance of the fitted semiparametric model with that of a parametric model. In general, the semiparametric model performed better than its parametric counterpart. We also addresse some concerns in using the proposed approach.Résumé : Le suivi des effets de l'éclaircie sur le microclimat fait partie intégrante de toute expérience d'éclaircie, car c'est en modifiant le microclimat que l'éclaircie affecte des processus écologiques importants. Une analyse efficace des données de suivi du microclimat devrait considérer à la fois l'influence du régime d'éclaircie sur le microclimat et les tendances temporelles de réponse du microclimat. La littérature sur l'éclaircie montre que peu d'études ont essayé d'aborder le second aspect, probablement parce qu'il est difficile de développer des modèles paramétrés pour les tendances temporelles. Les auteurs proposent l'utilisation de splines de lissage semi-paramétriques pour analyser les données de suivi provenant de dispositifs d'éclaircie. Le concept d'une spline de lissage est d'abord brièvement décrit. Ils fournissent ensuite un exemple dans lequel des données de suivi du microclimat provenant d'un dispositif d'éclaircie ont été analysées à l'aide de modèles de splines de lissage semi-paramétriques à effets mixtes. L'approche proposée a non seulement détecté les effets de l'éclaircie avec succès mais elle a également révélé des tendances temporelles inté-ressantes. Pour chaque variable microclimatique, ils ont aussi comparé les performances du modèle semi-paramétrique ajusté et d'un modèle paramétrique. De façon générale, les modèles semi-paramétriques étaient plus performants que leur contrepartie paramétrique. Ils ont également abordé certaines préoccupations concernant l'utilisation de l'approche proposée.[Traduit par la Rédaction] Guan et al. 1648
Taiwania (Taiwania cryptomerioides Hayata), a conifer native to Taiwan, is an economically important tree species due to its high resistance to insect infection and high wood utilization properties; however, when it was grown in clonal orchards, no filled seeds or fertile pollen were obtained. To address this reproductive dilemma, a suppressive subtractive hybridization (SSH) library was constructed from male cones, female cones and leaves. Reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed that two bark storage proteins, a betaphellandrene synthase, an endochitinase A2 precursor and two male-cone protein 1 precursors were specifically expressed in the reproductive organs of Taiwania. Comparisons of these two male-cone protein 1 precursors with those of Pinus radiata suggest that these genes may have different functions during different stages of male cone development and that different specific genes may be obtained from male cones collected at different stages of development.
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