Introduction
Study sites of Dahurian larch across northeastern China, including
Heilongjiang, Liaoning and Jilin provinces and the eastern part of the Inner
Mongolia Autonomous Region. Open circles represent natural forests and dots
represent planted forests.
Boreal forests, the second largest biome in the world, cover about one-third
of the Earth's forest area (Achard et al., 2006; Keenan et al., 2015).
Dahurian larch is a dominant tree species in Chinese boreal forest, which is
distributed primarily in northeast China. Dahurian larch forest is also the
predominant timber source in China, occupying 55 % of Chinese boreal
forest area and accounting for 75 % of Chinese boreal forest volume (Xu,
1998; Zhou et al., 2002). Dahurian larch forest is situated in the
southernmost part of the global boreal forest biome (Shugart et al., 1992)
and is undergoing great climatically induced changes. Thus understanding
the growth characteristics of Dahurian larch forest in China is of critical
need for management and prediction under future climate change.
Variable information in the data set, available at
https://doi.org/10.1594/PANGAEA.880984. N/A refers to values that are not applicable.
Column code
Definition
Unit
Number
Range
ID
Unique identification number of each record
N/A
743
1–743
Province
Province location of study site
N/A
4
N/A
Study site
Locality name of study site
N/A
122
N/A
Latitude
Latitude of study site
∘
743
40.85–53.47
Longitude
Longitude of study site
∘
743
118.20–133.70
Altitude
Altitude of study site
m
743
130–1260
Aspect
Slope direction of study site, including flat slope, sunny slope (south), half-sunny slope (west, southwest, southeast), shady slope (north) and half-shady slope (east, northwest, northeast)
N/A
289
N/A
Slope
Slope degree of study site
∘
346
0–60
Origin
Stand origin was classified into natural and planted forests
N/A
743
N/A
MAT
Mean annual temperature, from original study or other related reference
∘ C
743
-6.1–7.0
MAP
Mean annual precipitation, from original study or other related reference
mm
743
355–926
Age
Stand age, which is generally defined as age since germination in natural forest and since planting in planted forest; stand age is usually obtained from historical records or tree rings
years
743
1–280
Height
Mean tree height; the estimated tree height data from the power H–DBH equation were marked with E in the data set
m
708
0.24–29.4
DBH
Mean diameter at breast height; base diameter was only given in some young forests and marked with B in the data set
cm
664
0.70–34.9
Vtree
Mean tree volume; the estimated tree volume data from the two-variable larch equation were marked with E in the data set
10-3 m3/tree
663
0.04–936
Vstand
Stand volume; the estimated stand volume data from the estimated tree volume and stand density were marked with E in the data set
m3 ha-1
557
0.07–975
Density
Stand density/canopy density; planting density was only given
trees ha-1
623
213–13 275
in some studies and marked with P in the data set
%
139
0.2–1.0
Area
Plot area
m2
378
50–10 000
Plot
Plot numbers, i.e., replications
N/A
540
1–25
Year
Investigation year
N/A
500
1954–2014
Reference
Data sources; sources used to supplement climate information lacking in the original publications are denoted by asterisks in the data set
N/A
223
1965–2015
With the increased greenhouse effect and climate warming in recent years, forest
carbon sink has been paid more and more attention by the world (Bastin et
al., 2017). Forestation is the main measure to offset the greenhouse gas
emission and increase carbon sink (Fang et al., 2001). China has the largest
area of forest plantations in the world, approximately 79 million ha or
one-quarter of the world's total (FAO, 2015; Payn et al., 2015). Forest cover
showed an increasing trend through reforestation in northeast China (Achard
et al., 2006). Dahurian larch is an important fast-growing and cold-tolerant
tree species used in forestation in northeast China (Yang, 2009). Dahurian
larch is usually planted after fires or logging. The growth rates of Dahurian
larch plantations are important indexes in the assessment of forest recovery
processes and carbon sequestration potentials, which could supply strategies
for post-fire or post-harvest management (Huang, 2011). The data set can
provide a basis for evaluating and predicting carbon sequestration and
the potential of forestation activities.
Relating the easily measured variables (e.g., DBH, tree height) to other
structural and functional characteristics, is the most common and reliable
method for estimating forest biomass, net primary production and
biogeochemical budgets (Luo, 1996; Fang et al., 2001). Synthesis studies
mainly focused on larch biomass and net primary production with increasing
samples in recent decade in northeast China, for example, N=28 (Luo,
1996), N=17 (Wang et al., 2001a), N=18 (Wang et al., 2001b; Zhou et al.,
2002), N=36 (Wang et al., 2005), N=83 (Wang et al., 2008), N=50 (Zeng,
2015), N=150 (Zeng et al., 2017). However, large numbers of growth
measurements (e.g., age, DBH, tree height, volume) have scarcely been studied
systematically at the large scale. Therefore, a comprehensive growth data
set (N=743) of Dahurian larch in northeast China was developed in this
paper.
Data and methods
Research origin descriptors
The identity is as follows: “Growth data set of natural and planted Dahurian larch
in northeast China, version 1.0”.
The originators are as given below:
Bingrui Jia, State Key Laboratory of Vegetation and
Environmental Change, Institute of Botany, Chinese Academy of Sciences,
Beijing 100093, China;
Guangsheng Zhou, Chinese Academy of Meteorological Sciences,
Beijing 100081, China.
The period of study is from January 1965 to December 2015.
Objectives include conducting a complete literature review of
published studies on age, DBH, tree height and/or volume in natural and
planted Dahurian larch forests in order to construct a growth data set. The
data set can be used to analyze growth characteristics of Dahurian larch
forests and assess their potential productivity in future climate warming.
Site description
Site type. Data were derived from 122 study sites in
northeastern China. This region includes Heilongjiang, Liaoning and Jilin
provinces and the eastern part of the Inner Mongolia Autonomous Region (Fig. 1).
Habitat. Dahurian larch forest is naturally distributed in
the Great Xing'an Mountains of northeastern China. Dahurian larch is usually
planted in barren hills, post-fire areas or post-harvest areas in northeast China.
Climate. The climate in northeast China is controlled by the
high latitude East Asian monsoon, changing from cool temperate to temperate
zones from north to south, and from semi-arid to humid zones from west to
east. Mean annual temperature (MAT) for these sites ranged from -6.1 to 7.0 ∘C, and mean annual precipitation (MAP) ranged from 355 to 926 mm.
Data sources
Published studies (1965–2015) were collected from available online full-text
databases, including China Knowledge Resource Integrated Database
(http://www.cnki.net/, last access: 14 April 2018), China Science and Technology Journal Database
(http://www.cqvip.com/, last access: 14 April 2018), Wanfang Data Knowledge Service Platform
(http://www.wanfangdata.com/, last access: 14 April 2018), ScienceDirect (http://www.sciencedirect.com/, last access: 14 April 2018), ISI Web of Science (http://isiknowledge.com/, last access: 14 April 2018) and
Springer Link (http://link.springer.com/, last access: 14 April 2018). The different combinations of the
terms “Dahurian larch” (or “Larix gmelinii”) with “height”, “diameter at breast height
(or DBH)”, “tree volume” or “stand volume” were searched in full text.
Meanwhile, we also looked up related books (e.g., Ma, 1992; Wang, 1992;
Zhou, 1994; Yang, 2009). We attempted to compile a complete growth data set
of natural and planted Dahurian larch in the northeastern part of China (between
40.85 and 53.47∘ N; between 118.20 and
133.70∘ E).
Data collection criteria
Relationship between mean tree height and diameter at breast
height in the data set.
A critical review of the literature collected from the above-mentioned
sources was conducted to obtain reliable growth data using the following
criteria.
Scope. The objective of this study was to provide the data for
understanding growth characteristics of Dahurian larch natural forests (pure
Dahurian larch or its proportion more than 50 %) and monoculture
plantations. Forest stands included in the data set were restricted to those
not recently disturbed by logging, fires or insect pests. Additionally, the
following small numbers of special types were excluded: (i) Dahurian larch afforestation
in wetland (Li et al., 1985; Song and Li, 1990; Huang, 2011; Cui et al.,
2013), pastureland (Duan, 2005) or abandoned mine land (Yang et al., 2013);
(ii) hybrid test between Dahurian larch and other larch (Deng et al., 2010;
Zhang et al., 2005) and (iii) low-yield stands in hard environments (Wang et
al., 1979, 1991).
Study design and sampling. DBH and tree height were averaged
from the measurement values of all trees in plots or with a
random or systematic sampling method.
The tree regeneration layer, generally below
5 cm in DBH or 1.3 m in height, was neglected in the sampled plots. The stem volume
of individual tree was computed from felled wood samples or local tree
volume equations. The stand volume was usually calculated by multiplying the mean
individual volume by the stand density. Besides the growth data (i.e., DBH,
height and/or volume), the necessary information is provided in the
original sources, e.g., stand age, stand origin and study site.
Quality control. The data quality has been carefully reviewed
by the authors. Data have undergone substantial checking, for example,
a cross-check for relevant information from different sources and preliminary
correlation analysis among growth variables.
Consequently, 743 records that met the above criteria were selected to
develop a comprehensive growth data set of Dahurian larch in China. The data
set includes growth characteristics of Dahurian larch (i.e., mean tree height
(m), mean DBH (cm), mean tree volume (10-3 m3) and/or stand
volume (m3 ha-1)). In addition, associated information was included, if
available in original sources or ascertainable from other relevant
literature, i.e., geographical location (province location and locality
name of study site, latitude (∘), longitude (∘),
altitude (m), aspect and slope (∘)), stand description (origin,
stand age (years), stand density (trees ha-1) and canopy density), climate
(mean annual temperature (MAT, ∘ C) and mean annual precipitation
(MAP, mm)) and sample regime (observing year, plot size and number).
Table 1 lists these variables and their definitions, units, number and range.
Comparison of available tree volume from references with simulated
values from the two-variable tree volume equation
(Vtree=0.000050168241 DBH1.7582894H1.1496653).
Open circles (N=284) show that both tree height (H) and diameter at breast height (DBH)
are available in the references; solid circles (N=37) show that only DBH is available
in the references and H is estimated using the H–DBH model from Fig. 2.