用途：
DC3和DC4是DC1改進(jìn)版本。鋼絲繩的拉力改為徑向設(shè)置。這樣鋼絲繩對樹的壓力和樹徑無關(guān)，不同樹徑的測量結(jié)果可直接比較。傳感器通過一個由熱膨脹系數(shù)低的合金制成的鋼絲繩固定在樹上。用小塑料環(huán)減少鋼絲繩對樹的壓力，并減少摩擦阻力，大大提高靈敏度。
DC3和DC4的區(qū)別在于，DC4的測量范圍比較大， 如果樹桿比較粗或長得比較快，用DC4更合適。
應(yīng)用
植物生長過程的監(jiān)測
植監(jiān)測物的水分狀況。在以下方面：
-生態(tài)研究
-灌溉控制
環(huán)境因素對植物生長影響的研究
精準(zhǔn)確定每年的生長季節(jié)開始和結(jié)束的具體時間。
精準(zhǔn)判定霜凍事件的發(fā)生
植物水分和蓄水量的估算(結(jié)合液流量測量，可以連續(xù)計(jì)算蒸騰量)
監(jiān)測和調(diào)查森林、道路和公園樹木或樹枝的穩(wěn)定性
果蔬貯藏過程中水分的流失
多年生植物(例如樹木)的典型植物生長曲線是什么樣子的，它能告訴我們什么：
(右圖)是連續(xù)測量的樹木生長曲線。(A)連續(xù)數(shù)據(jù)揭示了直徑增長動態(tài)的年際差異，即生長周期的開始和結(jié)束以及直徑增長的速度(曲線斜率)。
在白天的時間尺度上(如圖所示)。(B)直徑變化過程顯示出蒸騰耗水量高的時期，干旱時期表現(xiàn)為樹干的強(qiáng)烈收縮和膨脹(高日徑變化)。在降雨過程中，蒸騰耗水量是很小，莖稈內(nèi)水分得到補(bǔ)充，如微弱的日莖稈變化和莖稈大小回歸生長曲線(黑色的虛線圖)所表明的那樣。
特點(diǎn)：
·適合于直徑大于> 5厘米的樹；
·鋼絲繩對樹的壓力和樹徑無關(guān)，不同樹徑的測量結(jié)果可直接比較；
·鋼絲繩的拉力根據(jù)樹徑自動調(diào)整，反應(yīng)敏感；
· 對植物無損傷；
·可抗拒風(fēng)，雪，下跌小樹枝和小果實(shí)的影響，保證穩(wěn)定測量；
·易于安裝；
·用花蘭螺絲簡化復(fù)調(diào)；
·數(shù)據(jù)必須經(jīng)過換算才能取得周長變化（有免費(fèi)Excel程序）；
· 測量的樹干最好接近圓形；
·耗電少，比如用DL10 數(shù)采，一個內(nèi)置普通電池可連續(xù)記錄兩年以上的數(shù)據(jù)；
· 有15年全球不同地帶成功使用的經(jīng)驗(yàn)（極地地區(qū)，熱帶，高山，沙漠）；
·分辨率高達(dá)0.03微米（取決于數(shù)采的分辨率）；
·探頭溫度補(bǔ)償；
·與常用數(shù)采兼容，如Delta-T Logger， Campbell Logger， DataTaker Logger。
技術(shù)參數(shù)：
DC3周長生長測量傳感器 | |
適用于樹桿直徑 | >5厘米 |
傳感器測量范圍 | 25.4毫米 |
復(fù)調(diào)測量范圍 | 無限 |
一次測量范圍 |
|
準(zhǔn)確度 | ±（測量值的0.04%+0.6微米） (CR300 Logger) ±（測量值的0.1%+1微米） (DL18 Logger) |
分辨率 | 0.03-6微米（取決于使用的數(shù)采） |
線性系數(shù) | <0.7% |
傳感器的溫度系數(shù) | <0.1微米/度 |
鋼絲繩熱膨脹系數(shù) | <1.4 ×10-6/K |
重量（僅傳感器） | 37g |
傳感器電纜長度 | 5m，可擴(kuò)展至最大100m |
工作條件 | 溫度范圍 -25–70 °C, 濕度范圍 0-100％ |
生長測量儀數(shù)采 | |
連接生長測量儀數(shù)目 | 1~4個 |
分辨率 | 0.3-0.6 微米（和生長測量儀的型號有關(guān)） |
內(nèi)存 | 1 900 000個數(shù)據(jù)內(nèi)存（連4個生長測量儀，每分鐘測一次， 可存一年的數(shù)據(jù)） |
接口 | USB |
電池 | 一個內(nèi)置電池可連續(xù)使用一年以上 |
防水 | 是 |
以下是來自廠家的一封Email：
Important product information: Deviation in quality of fastening elastic band DC and DDL
Dear Customer,
unfortunately, we have to inform you that in the case of the dendrometer products of the model series DC (DC3, DC4) and DD-L (DD-L1, DD-L2, DD-L3) there has been a quality deviation in the area of the fastening rubber bands. In this context, Unfortunately, we have now been told by some of our customers that the fastening rubber band on individual dendrometer devices of the above-mentioned model series does not correspond to the otherwise usual high quality, but rather begins to tear after a short period of use.
Affected are deliveries between March 1st, 2021 and August 15th, 2021.
You have received this letter because at least one of your this year’s orders of DC or DD-L dendrometers falls within the specified delivery period and may therefore be affected.
We apologize very much for this quality deviation.
However, since by far not all devices from the above-mentioned period are affected by the deviation, a general replacement of all rubber bands does not seem appropriate.
We therefore ask you to contact us if your customers, or you yourself as the end customer, should also notice such a defect in your DC or DD-L products.
We will then arrange for a replacement of the fastening rubber immediately.
Due to the far-reaching consequences of the Covid19 pandemic on global supply chains, we were unfortunately also forced to use alternative products from new suppliers in the case of a few components in our sensor products. Unfortunately, in such cases, even a detailed comparison of manufacturer specifications, as well as our additional tests carried out in-house, cannot entirely replace the many years of experience and meticulous selection of our usual components and well-known suppliers.
Thank you for your understanding and with best regards,
Michael Goisser
--
Dr. Michael Goisser
Sales Manager
Applications Scientist
ECOMATIK GmbH
