Abstract
A comprehension of the effects planting density and nitrogen (N) fertilization have on the physiological and morphological characteristics of trees is critical for optimizing the require size and characteristics of wood products. We evaluated the growth traits and the leaf and wood characteristics of three clone poplars including Populus simonii × P. nigra ‘Xiaohei’, ‘Xiaohei-14’ and ‘Bailin-3’ under five planting densities (1666, 1111, 833, 666, and 555 tree ha−1) and four N fertilization rates (0, 100, 160, and 220 g tree−1 year−1). The results show that the clone type significantly affected all observed indicators, while planting density and N fertilization treatments had a significant effect on growth traits and leaf characteristics, but not on wood characteristics. Specifically, the clone ‘Bailin-3’ exhibited the largest annual increments in tree height and diameter at breast height (DBH), leaf width, N content, and soluble protein content. A decrease in initial planting density (from 1666 to 555 tree ha−1) led to an increased annual incremental tree height and DBH, regardless of clone type and N fertilization treatment. N fertilization treatment significantly impacted the annual increment in DBH, but not that of tree height. Further, the annual increments in tree height and DBH were positively correlated with leaf width, N content, chlorophyll content, and soluble protein content, and negatively correlated with hemicellulose content. In addition, the chlorophyll and soluble protein contents were identified as the most reliable predictors of the annual increments in tree height and DBH. Our results demonstrate the clone ‘Bailin-3’ with 555 tree ha−1 under 160 g N tree−1 yr−1 showed superior growth traits and leaf characteristics. Thus, it is recommended for future poplar silviculture of larger diameter timber production at similar sites. The results contribute to understanding of the effects of planting density and fertilization on the growth traits and the leaf and wood characteristics of three poplar clones, offering valuable guidance for the sustainable development and long-term productivity of poplar plantations.
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Claims 16
Claim · model-written summary
Clone type significantly affected all observed indicators.
PopulusNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the clone type significantly affected all observed indicators”
t0“Three Poplar Clones”
Claim · model-written summary
Planting density significantly affected growth traits and leaf characteristics.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“planting density and N fertilization treatments had a significant effect on growth traits and leaf characteristics, but not on wood characteristics”
t0“Three Poplar Clones”
Claim · model-written summary
Nitrogen fertilization significantly affected growth traits and leaf characteristics.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“planting density and N fertilization treatments had a significant effect on growth traits and leaf characteristics, but not on wood characteristics”
t0“Three Poplar Clones”
Claim · model-written summary
Planting density had no significant effect on wood characteristics.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“planting density and N fertilization treatments had a significant effect on growth traits and leaf characteristics, but not on wood characteristics”
t0“Three Poplar Clones”
Claim · model-written summary
Nitrogen fertilization had no significant effect on wood characteristics.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“planting density and N fertilization treatments had a significant effect on growth traits and leaf characteristics, but not on wood characteristics”
t0“Three Poplar Clones”
Claim · model-written summary
Bailin-3 had the largest annual height and diameter increments and leaf width.
- Material
- Bailin-3e0
- Outcome
- annual increments in tree height and diameter at breast height (DBH), leaf widthe0
- Direction
- largeste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the clone ‘Bailin-3’ exhibited the largest annual increments in tree height and diameter at breast height (DBH), leaf width, N content, and soluble protein content”
t0“Three Poplar Clones”
Claim · model-written summary
Bailin-3 had the largest leaf nitrogen and soluble protein contents.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the clone ‘Bailin-3’ exhibited the largest annual increments in tree height and diameter at breast height (DBH), leaf width, N content, and soluble protein content”
t0“Three Poplar Clones”
Claim · model-written summary
Reducing planting density increased annual height and diameter increments.
- Treatment
- decrease in initial planting density (from 1666 to 555 tree ha−1)e0
- Outcome
- annual incremental tree height and DBHe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A decrease in initial planting density (from 1666 to 555 tree ha−1) led to an increased annual incremental tree height and DBH, regardless of clone type and N fertilization treatment.”
t0“Three Poplar Clones”
Claim · model-written summary
Nitrogen fertilization significantly affected annual DBH increment.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N fertilization treatment significantly impacted the annual increment in DBH, but not that of tree height.”
t0“Three Poplar Clones”
Claim · model-written summary
Nitrogen fertilization did not significantly affect annual height increment.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N fertilization treatment significantly impacted the annual increment in DBH, but not that of tree height.”
t0“Three Poplar Clones”
Claim · model-written summary
Annual height and DBH increments were positively correlated with leaf width and nitrogen content.
- Organ / stage
- leaf width, N contente0
- Outcome
- annual increments in tree height and DBHe0
- Direction
- positively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the annual increments in tree height and DBH were positively correlated with leaf width, N content, chlorophyll content, and soluble protein content”
t0“Three Poplar Clones”
Claim · model-written summary
Annual height and DBH increments were positively correlated with chlorophyll and soluble protein content.
- Compound
- chlorophylle0
- Outcome
- annual increments in tree height and DBHe0
- Direction
- positively correlatede0
- Qualifier
- soluble protein contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the annual increments in tree height and DBH were positively correlated with leaf width, N content, chlorophyll content, and soluble protein content”
t0“Three Poplar Clones”
Claim · model-written summary
Annual height and DBH increments were negatively correlated with hemicellulose content.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“negatively correlated with hemicellulose content”
t0“Three Poplar Clones”
Claim · model-written summary
Chlorophyll and soluble protein contents were the most reliable predictors of annual height and DBH increments.
- Compound
- chlorophylle0
- Outcome
- annual increments in tree height and DBHe0
- Comparator
- most reliable predictorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the chlorophyll and soluble protein contents were identified as the most reliable predictors of the annual increments in tree height and DBH”
t0“Three Poplar Clones”
Claim · model-written summary
Bailin-3 at 555 trees per hectare and 160 g N per tree yearly showed superior growth and leaf traits.
- Material
- Bailin-3e0
- Treatment
- 555 tree ha−1 under 160 g N tree−1 yr−1e0
- Outcome
- growth traits and leaf characteristicse0
- Direction
- superiore0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the clone ‘Bailin-3’ with 555 tree ha−1 under 160 g N tree−1 yr−1 showed superior growth traits and leaf characteristics”
t0“Three Poplar Clones”
Claim · model-written summary
Bailin-3 at the stated density and nitrogen rate was recommended for larger diameter timber at similar sites.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it is recommended for future poplar silviculture of larger diameter timber production at similar sites”
The same questions in other papers
density · growth · Populus (poplar)Positive and negative results
5 papers in the same direction as this paper · 2 in the opposite direction
- positive
- negative
- negative
4 papers more in this group
See all 8 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.