Comparison of the pilodyn and torsiometer methods for the rapid assessment of wood density in living trees
Comparison of the pilodyn and torsiometer methods for the rapid assessment of wood density in living trees
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发表时间：
1978-12
影响因子：
1.5
通讯作者：
D. Cown
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作者：
D. Cown
为了评价“Pilodyn木材测试仪”(通过测量钢钉的穿透度来操作)对活着的树木的木材密度进行无损评估，进行了两个实验。结果与最近发展的扭矩计法的结果进行了比较，以预测从增量芯材测量的木材密度的准确性。在第一次试验中，对10年生辐射松无性系进行了测试(25个无性系，5个分株/无性系，2个尺寸/分株)。Pilodyn法是迄今为止最快速的方法，渗透数据与无性系平均木材密度的相关系数为-0.96。扭力计给出的关联度为0.78。第二项研究是在一个31年生的辐射松人工林中，用第一次试验中使用的三种方法在四个胸高采样点对25株树干进行了评估。同样，Pilodyn结果得到的速度更快，与平均树木外木材密度的相关性更密切(r=-0.86，而扭力计为0.79)。Pilodyn木材测试仪在快速测量大量树干中的木材密度方面具有很高的潜力，对于按密度类别对无性系或家系等树木组进行排序特别有用。前言木材密度是辐射松树育种计划中越来越多地考虑的一个重要木材特性，它与活力、形状、分枝和健康一起被考虑。然而，由于这是到目前为止大规模测量这些特征中最昂贵的，考虑到所涉及的时间，它通常不被评估。快速测量立木木材密度的方法备受追捧，近年来出现了扭力计技术(图1)，通过扭矩测量装置记录转动增量钻所需的力(Polge和Keller，1970；Harris等人，1976a；Nicholls和Roget，1977；Young，1977)。该系统仍然需要在田间使用增量式钻孔机，但大大减少了实验室的工作量。Pilodyn木材测试仪(图1)最初是在瑞士开发的，目的是获得有关木杆软腐烂程度的定量数据。这项测试涉及新泽西州。SCI。8(3)：384-91(1978)。图1(上)：安装在增量式钻头上的扭力计(下)Pilodyn木材试验机。386《新西兰林业科学杂志》第8卷将一枚弹簧式打击针注入木头，并根据仪器本体上的刻度读出穿透深度。Hoffmeyer(1978)报告了使用Pilodyn估计冷杉木材密度的小规模试验结果。获得了穿透深度与增量芯密度的相关系数为0.71。这一原理很有吸引力，因为它是快速的，不需要使用增量钻孔器，并且应该没有操作员偏见。采用6焦耳弹簧的Pilodyn和直径2.5 mm的针杆，研究了辐射松立木的穿透深度与木材密度的关系。材料和方法1.对206个辐射松无性系的10年生分株进行了鉴定。1350年，1968年以随机区为单位的卡金加罗亚森林。因此，在进行本评估时，这些插穗已经在地里待了10年。在1974年的一次测量中(Wilcox等人，1975)根据增加的岩芯计算了密度值，并将这些数据用作在试验中选择覆盖全部密度范围的25个无性系的基础。在该地区的平面图上随机确定了25个无性系中每一个的5个分株，并用Pilodyn、扭转仪和增量岩芯进行了测试。在每个分株上，从胸高的茎的两侧移除两个树皮条(20 mm×50 mm)，这定义了所有测量和核心的测试区域。由于死亡率高，其中三个克隆后来不得不被丢弃。在实验室中，用最大含水率法(Smith，1954)评估了外部三个完整的年轮的木材密度。2.在一座有51年树龄的林分中进行评估，因为皮洛丹松是通过渗透来运作的，有人怀疑它的行动可能会受到遇到的晚材带数量的影响，因为辐射松的晚材密度明显大于早材，并且反差随着距离髓的距离而增加。Cpt的一个31岁的展台。10瓦卡雷韦尔瓦国家森林公园被选为测试该仪器在评估老林分密度方面的适用性。所采用的方法与实验1相同，只是每棵树在25个树干上测试4个样本点，以便将单株树木的密度排序与Pilodyn和Torsieter结果进行比较。在实验室中，每个增量岩心的外部20 mm用于密度测定。
Two experiments were carried out to evaluate the "Pilodyn Wood Tester" (which operates by measuring the penetration of a steel striker pin) for nondestructive assessment of wood density in living trees. Results were compared with those from the recently developed Torsiometer method as regards accuracy for predicting the wood density measured from increment cores. In the first trial, 10-year-old radiata pine clones were tested (25 clones, 5 ramets/clone, 2 measurements/ramet). The Pilodyn was by far the most rapid method and the penetration data gave a correlation coefficient of —0.96 with wood density on a clone mean basis. The Torsiometer gave a correlation of 0.78. The second study was in a 31-year-old radiata pine plantation where 25 stems were assessed at four breast height sampling points by the three methods used in the first trial. Again the Pilodyn results were obtained more rapidly and were more closely related to mean tree outerwood density (r = —0.86 as compared to 0.79 for the Torsiometer). The Pilodyn Wood Tester appears to have a high potential for the rapid measurement of wood density in large numbers of stems and would be particularly useful for ranking groups of trees such as clones or families by density classes. INTRODUCTION Wood density is an important timber characteristic which is being increasingly considered in radiata pine tree breeding programmes along with vigour, form, branching and health. However, because it is by far the most expensive of these traits to measure on a large scale, on account of the time involved, it is often not assessed. Rapid methods of measuring wood density in standing trees are much sought after and recent years have seen the development of the Torsiometer technique (Fig. 1) whereby the force required to turn an increment borer is recorded with the aid of a torque-measuring device (Polge and Keller, 1970; Harris et al., 1976a; Nicholls and Roget, 1977; Young, 1977). This system still necessitates the use of an increment borer in the field but greatly reduces the laboratory workload. The Pilodyn Wood Tester (Fig. 1) was originally developed in Switzerland to obtain quantitative data on the degree of soft rot in wooden poles. The test involves N.Z. J. For . Sci. 8(3): 384-91 (1978). No. 3 Cown — Assessment of Wood Density in Living Trees 385 FIG. 1 (Upper)-Torsiometer attached to increment borer bit (Lower) Pilodyn Wood Tester. 386 New Zealand Journal of Forestry Science Vol. 8 injecting a spring-loaded striker pin into the wood and reading the depth of penetration off a scale on the body of the instrument. Hoffmeyer (1978) reported results of a smallscale trial using the Pilodyn to estimate the wood density of Abies alba trees. A correlation coefficient of 0.71 was obtained for the data relating penetration depth to the density of increment cores. This principle is attractive in that it is rapid, does not require the use of an increment borer, and should be free of operator bias. The following studies were undertaken to examine the relationship between penetration depth and wood density of standing trees of Pinus radiata D. Don, using a Pilodyn with a 6-joule spring and 2.5-mm diameter striker pin. MATERIALS AND METHODS 1. Assessment on 10-year-old Trees Ramets from 206 radiata pine clones were established in Cpt. 1350, Kaingaroa Forest in 1968 in randomised blocks. Thus at the time of the current assessment the cuttings had been in the field for 10 years. Density values were calculated from increment cores at a 1974 measurement (Wilcox et al., 1975) and these data were used as a basis for the selection of 25 clones covering the full range of densities in the trial. Five ramets from each of the 25 clones were identified at random on a plan of the area and these were to be tested with the Pilodyn, Torsiometer and increment cores. At each ramet, two bark strips (20 mm X 50 mm) were removed from opposite sides of the stem at breast height and this defined the test areas within which all measurements and cores were foken. Three of the clones had to be subsequently discarded due to high mortality. In the laboratory the outer three complete growth rings were assessed for wood density by the maximum moisture content method (Smith, 1954). 2. Assessment in a 51-year-old Stand As the Pilodyn operates by penetration, there was a suspicion that its action might be affected by the number of latewood bands encountered, as latewood density in radiata pine is appreciably greater than that of the earlywood, and the contrast increases with distance from the pith. A 31-year-old stand in Cpt. 10 Whakarewarewa State Forest Park was chosen to test the suitability of the instrument for assessing density in older stands. Methods adopted were the same as for Experiment 1 except that four sample points per tree were tested from each of 25 stems in order to compare the ranking of individual trees by density with the Pilodyn and Torsiometer results. In the laboratory the outer 20 mm of each increment core were used for density determination.