The effect of end-point adjustments on smoothing splines used for tree-ring standardization |
| |
| Affiliation: | 1. Indiana University, Department of Statistics, Informatics East, 919 E. 10th St., Bloomington, IN 47408, United States;2. Indiana University, Department of Geography, Student Building 120, 701 E. Kirkwood Ave., Bloomington, IN 47405, United States;1. School of Environment, The University of Auckland, Auckland, New Zealand;2. University College London, Institute of Archaeology, London, UK;3. Oxford Dendrochronology Laboratory, Oxford, UK;1. Slovenian Forestry Institute, Department of Forest Yield and Silviculture, Večna pot 2, 1000, Ljubljana, Slovenia;2. University of Zagreb, Faculty of Forestry, Department of Forest Inventory and Management, Svetošimunska 25, 10000, Zagreb, Croatia;3. Institute of Lowland Forestry and Environment, University of Novi Sad, Antona Čehova 13 D, 21000, Novi Sad, Serbia;1. National Institute for Research and Development in Forestry "Marin Drăcea", Calea Bucovinei, 73 bis, 725100, Câmpulung Moldovenesc, Romania;2. Icelandic Forest Research, Mógilsá, IS-162 Reykjavík, Iceland;3. Department of Geography, Universităţii 13, 720229, Ștefan cel Mare University of Suceava, Romania;1. Département de biologie, chimie et géographie et Centre d’études nordiques, Université du Québec à Rimouski, 300 Allée des ursulines, Rimouski, QC G5L 3A1, Canada;2. Institut National de la Recherche Scientifique, 490 de la Couronne, Québec, QC G1K 9A9, Canada;1. Pyrenean Institute of Ecology, IPE-CSIC, Avda. Montañana 1005, 50059, Zaragoza, Spain;2. Department of Geography, University of the Balearic Islands, Carr. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain;3. Área de Botánica, Departamento de Ciencias Agroforestales, EiFAB, iuFOR-Universidad de Valladolid, Campus Duques de Soria, 42004, Soria, Spain;4. Dept. Biologia Evolutiva, Ecologia i Ciències Ambientals, Univ. Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain;5. Fakulteti i Shkencave Pyjore, Universiteti Bujqësor i Tiranës, 1029, Tirana, Albania;6. Ionplus AG. Lerzenstrasse 12, 8953, Dietikon, Switzerland;1. Consiglio per la Ricerca e la sperimentazione in Agricoltura, Forestry Research Centre (CRA-SEL), Viale S. Margherita 80, 52100 Arezzo, Italy;2. Università Politecnica delle Marche, Department of Agricultural, Food and Environmental Sciences, Via Brecce bianche, 60121 Ancona, Italy |
| |
| Abstract: | The cubic smoothing spline has been a popular method for detrending tree-ring data since the 1980s. The common implementation of this procedure (e.g., ARSTAN, dplR) uses a unique method for determining the smoothing parameter that is widely known as the %n criterion. However, this smoothing parameter selection method carries the assumption that end point effects are ignorable. In this paper, we complete the mathematical derivation and show how the original method differs from the complete version, both in the interpretation of the smoothing parameter and in the spline fit. Frequency response curves (FRC) demonstrate how the smoothing parameter is affected by the original assumption. For example, the FRC results indicate that a tree core of 250-year length has a 14% difference in the cut-off frequency when looking at the 67%n criterion. The FRC analysis shows that the existing approach produces a more flexible fit than anticipated, i.e., it is removing more variance than previously thought. For example, a 67%n spline under the existing approach corresponds to a 53%n spline fit. By using both simulated tree-core sequences and a dataset from a Midwest forest, we discuss which conditions result in greater differences between the spline fits and which conditions will have small differences. Tree-core sequences that have more curvature, such as a large-amplitude growth release, will lead to greater differences. Finally, we provide approximations to the end-point effect procedure. For example, using an 83%n criterion under the original approach produces a spline fit approximating the 67%n fit under the complete approach. These approximations could be easily implemented within existing programs like ARSTAN. |
| |
| Keywords: | Cubic smoothing spline Dendrochronology Detrending End-point effects Frequency response curves |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
