LU502244B1 - A Tending Method for Recovering Subtropical Secondary Forest - Google Patents

Abstract

The invention comprises the following steps: distinguishing different damaged types of individual trees, counting the individual distribution density and the proportion in the stand of different damaged types of trees; According to the ranking of the highest proportion of damaged types, the important value of damaged trees and the distribution proportion, determine the main damaged trees and the main damaged types; Based on the sprouting rate and living change annually of individuals with different damaged types, the tending management of main damaged trees was carried out. According to the invention, the secondary forest is nurtured managed by using individual sprouting and sprouting of different damaged types of trees, which slows down the resource competition of early-stage broken-tip trees and fallen-down trees and shortens the adverse impact of self-thinning process on the service function of forest ecosystem, promotes sprouting and sprouting, shortens the recovery time of subtropical secondary forest after disaster.

Description

DESCRIPTION A Tending Method for Recovering Subtropical Secondary Forest 7902248

TECHNICAL FIELD The invention relates to a tending method for recovering subtropical secondary forest, in particular to a tending method for promoting the recovery of subtropical secondary forest by sprouting and renewing individual shoots of different damaged types.

BACKGROUND As global change intensifies, extreme weather events occur more and more frequently, and the frequency and intensity of natural disasters such as snow storms and fires also change. In recent years, a series of extreme weather events are fresh in our memory, such as the ice storm in North America in 1998, the drought in North America in 2002, the drought and heat wave in Europe in 2003, Hurricane Katrina in 2005, the freezing rain in the eastern United States in 2007 and Hurricane Ike in 2008. Extreme weather events, such as the snow and ice disaster in southern China in 2008 and the drought in southwest China in 2010, have caused serious harm to the natural and human systems in the affected areas, and caused great losses to the economy, society and ecology.

After being disturbed by man-made (felling) or natural disturbance (ice and snow disaster, fire, wind disaster, etc.), plants will continue to survive through seed renewal or sprout renewal. Seed regeneration needs to go through a long process of germination, settlement, competition, etc., and sprout regeneration is a shortcut for plants to compete for survival in situ, especially in the early stage of community recovery. Sprouting regeneration is one of the effective ways for plants to adapt to various disturbance stresses, which has an important influence on the dynamics of plant communities. It is an important way to maintain the continuity and stability of the population by maintaining the population number and quickly recovering and perfecting the structure and function of forest plant communities through germination regeneration. After the communities with strong germination ability are disturbed, because for the (persistence niche) effect, the budding plants often have strong self-balancing ability and resilience, and have strong stability, which makes the vegetation succession keep a good continuity.

The catastrophic snow and ice disaster in southern China in January 2008 provided a natural laboratory for studying the forest snow disaster and its rare and strong influence on the canopy structure of tropical and subtropical evergreen broad-leaved forests in China. After the ice storm, a large number of damaged Schima superba individuals quickly sprouted shoots to make up for the short-term carbon loss caused by canopy biomass loss. In subtropical forests, the initiation and regeneration of woody plants have received little attention. Regeneration, as a key functional trait in plant ecology, is an effective means for woody plants to recover the biomass lost during disturbance. 5022044 Schima superba is an important tree species in subtropical evergreen broad-leaved forest in China, and it is also the main tree species in fire protection forest belt. Because of its shade tolerance, fluctuation and opportunity of regeneration, it is the dominant species in succession series or climax community. In the snow and ice disaster in 2008, the subtropical secondary evergreen broad-leaved forest dominated by Schima superba was seriously damaged, and the arbor species suffered from the effects of stem breaking, branches breaking or roots lodging, and the forest landscape and stand structure changed accordingly, and the microenvironment in the ecosystem changed, which had a profound impact on the direction and way of forest community development and succession.

How does germination ability change with age? With the recovery of damaged trees, it is unknown how the germination ability of trees changes with age. After extreme disturbance, how trees can keep sprouting is also related to its sprouting location. Under the background of global climate change, it is particularly important to make full use of the law of tree sprouting after the disaster, and to realize the rapid recovery of damaged subtropical secondary forest after the disaster through rational management at the early stage of sprouting.

SUMMARY The purpose of the present invention is to provide a tending method for promoting the recovery of subtropical secondary forest by utilizing the initiation and renewal of individuals with different damaged types.

In order to solve the above technical problems, the present invention provides the following technical solutions: The invention provides a tending method for recovering subtropical secondary forest, which comprises the following steps: Distinguish different damaged types of individual trees, and count the individual distribution density and proportion of different damaged types of trees in the stand; According to the ranking of the highest proportion of damaged types, the important value of damaged trees and the distribution proportion, determine the main damaged trees and the main damaged types; Based on the sprouting rate and living change annually of individuals with different damaged types, the tending management of main damaged trees was carried out.

Preferably, the different damage types are undamaged, dead, rummaging, tilting, bending, broken tip, broken branch and trunk.

Preferably, the main damaged trees are Schima superba, and the main damaged types of Schima superba are broken-tip trees, turned-over trees and inclined trees.

Preferably, for broken-tip trees, thin sprouting strips at the base of the trunk, the middle and lower parts of the trunk should be promptly thinned, and 2-3 thicker sprouting branches at the 50224 top of the trunk canopy should be kept, and excess sprouting branches at the top should be removed.

Preferably, from the 3rd year after the disaster, before the germination in autumn, the young sprouting strips in the middle and upper part of the trunk should be removed, and the thicker sprouting strips in the base of the trunk should be kept.

Preferably, for inclined trees, from the 3rd year after the disaster, the young sprouting strips of the trunk are removed, and the thicker sprouting strips in the middle and middle-upper part of the trunk are kept.

Preferably, the new sprouting strips in the year after the disaster and the 2 year after the disaster are reserved for different damaged types, so as to promote germination and rejuvenation.

Preferably, in the year 3 after the disaster, that is, during the canopy restoration of the secondary forest, the trunk section far from the base of the trunk should be cut off in time, and the trunk section at the lower part of the trunk should be kept.

Preferably, in the present invention, Individual tree distribution = number of damaged trees of various types/plot area; Proportion in forest (%) = number of damaged trees of various types/total number of trees in sample plot *100%.

Preferably, in the present invention, the dynamic monitoring method of sprouting rate and living change annually includes: at the end of the growing season, respectively measuring the number and location of sprouting at the first time after the disaster according to the damage types, repeating the above index monitoring every year, calculating sprouting rates and survival dynamics of different damaged types, and evaluating the sprouting renewal and recovery of different damaged types of trees according to the changes of sprouting rate and survival dynamic indexes of damaged types.

Further, the sprouting rate (%) = the number of newly sprouted sprouts per year/the total number of existing sprouts in the trunk * 100%; The dynamic calculation of sprout survival is expressed according to the ratio of the number of existing sprouts in each year to the total number of sprouts in the previous year.

Compared with the prior art, the invention has the following technical effects: In the recovery process of damaged subtropical natural secondary forests after disasters, the invention utilizes individual germination and sprouting of different damaged types of trees to nurture and manage the secondary forests, which slows down the adverse effects of the resource competition of early-stage broken-tip trees and fallen-down trees and shortening the self-thinning process on the service function of forest ecosystem, promotes germination and sprouting, and shortens the recovery time of subtropical secondary forests after disasters. 7902248 According to the difference of sprout renewal rules of different damaged types, the invention puts forward a management scheme for sprouting of trees with different damaged types, determines the reasonable time for thinning (removing) sprouting, timely reduces the number of sprouting in the trunk section, relieves the competition pressure of sprouting population resources, and at the same time, fully improves the resource utilization capacity by removing the trunk section during the reasonable recovery period of the tree, and also slows down the resource competition pressure on the broken-tipped trees, so that the broken-tipped trees with low damage degree can be recovered as soon as possible to form the crown before the disaster.

DESCRIPTION OF THE INVENTION The invention provides a tending method for promoting the recovery of subtropical secondary forest by utilizing the initiation and renewal of individuals with different damaged types, which comprises the following steps: S1. Distinguish different damage types of individual trees: Based on the background investigation data of damaged natural secondary forests after the disaster, 8 different damage types were investigated according to the main affected tree species.

The 8 different damage types are identified according to the following definitions: (1) Definition of different types of damage: undamaged, dead, uprooted, tilting, bending, broken tip, broken branch and trunk; (2) See Table 1 for the definition of damage types.

Table 1 Definition of individual damage types of damaged trees after disaster LU502244 Visual inspection shows that the trunk and branches are not obviously Undamaged Le After the disaster, the root soil is completely separated, or the plant stem The root disk of the tree is exposed, and the root chassis can be seen. Uprooted | Only one side of the root system is connected with the soil, and the branches are broken or unbroken. The trunk is inclined, but not bent, and the root system is connected with Slanting | the soil as a whole, but the soil around the bottom of the trunk is loose, the root disk is invisible, and the branches and tips are broken or unbroken; The trunk is bent, the root system is connected with the soil as a whole, The trunk is upright, the top of the tree is broken, the broken tree is in Broken tip oc nie. Folding | The trunk is upright, only the branches are broken, and the rest are Broken The trunk breaks at any place below the bottom of the crown, Ummm S2. Statistics on individual distribution density and proportion in stand of different damaged trees: according to the representative fixed sample plot (20mx20m), investigate each tree (individuals with basal diameter > 4cm), and record the name, damaged type and grade, DBH (DBH, 1.3m), height (H) and crown width of each tree.

Further, in step S2, the individual distribution density and the proportion in the stand of different damaged trees are calculated as follows: Distribution = number of damaged trees of various types (trees)/plot area (m?), and the proportion (%) = number of damaged trees of various types (trees)/total number of trees in plot *100%.

S3. According to the proportion of damaged types, rank the highest and the important value and distribution proportion of damaged trees, and determine the main damaged trees.

According to the background data of fixed sample plots (including DBH, tree height, crown width, etc. of tree species in the sample plots, as well as 8 damaged types to which individual trees belong), the important value of each damaged type, the number of distributed individuals and their proportion of different damaged trees were calculated, and the names of main damaged trees and the main damaged types of each tree species were determined according to the proportion of different damaged types of individual trees. In the specific embodiment of the 50224 invention, Schima superba is a tree species with an important value greater than 10 and the highest value in the damaged natural secondary forest, and is a dominant tree species in the damaged secondary forest.

Furthermore, in step S3, the main tree species of damaged secondary forest in the experimental investigation area are Schima superba, Cunninghamia lanceolata, Pinus massoniana, Castanopsis sclerophylla, Castanopsis fabri Hance, Cyclobalanopsis glauca (Thunberg) Oersted, Phyllostachys pubescens, etc. However, except for Schima superba, Cunninghamia lanceolata and Pinus massoniana, the important value of trees is greater than

10.0, and other broad-leaved trees are less than 5.0. Therefore, considering the important value, the damage rate and the composition of important fire-resistant tree species, the germination and regeneration characteristics of Schima superba are mainly studied.

Furthermore, the important value in step S3 is calculated according to the following formula: the important value of trees = (relative density+relative significance+relative frequency) /3. Where the relative density (RD) = (density of a certain plant/total density of all plants) x100= (number of individuals of a certain plant/number of individuals of all plants)x 100; Significance = (Cross-sectional area of tree breast height of this individual in the sample plot and/or the sum of all individual cross-sectional area of tree breast height in the sample plot) x 100%; Relative frequency = (frequency of this species/sum of frequencies of all species) x100%.

Furthermore, the average density of Schima superba, the main damaged tree, is 2400+ha-1, the stand base area (BA) is 27.14m2-ha-1, the DBH is up to 25 cm, and the average DBH is 12.5 cm.

S4. According to the proportion of different damaged types of Schima superba, it is determined that the main damaged types of Schima superba are broken-tip wood, turned-over wood and inclined wood.

SS. Based on the sprouting rate and living change annually of individuals with different damaged types, the tending management of broken-tipped trees, turned-over trees and inclined trees was carried out.

The dynamic monitoring method of sprouting rate and living change annually of sprouting strips includes: at the end of growing season, respectively measuring the number and occurrence position of sprouting strips in the first time after disaster according to damage types. Repeat the monitoring of the above indicators every year, and calculate the sprouting rate and sprouting survival dynamics of different damaged types, according to the sprouting rate (%) = the number of newly sprouted sprouts per year/the total number of existing sprouts in the trunk * 100%; The dynamic calculation of sprout survival is expressed according to the ratio of the number of existing sprouts in each year to the total number of sprouts in the previous year. According to the 50224 changes of sprouting rate and survival dynamic indexes of damaged types, the regeneration and recovery of sprouting strips of broken-tip trees, turned-over trees and inclined trees were evaluated.

Specifically, in step S5, the dynamic monitoring of sprout growth of three different damaged types includes: (1) At the first time after the disaster, according to different main disaster types, 30 sample trees were randomly selected and listed as long-term observation samples to study the characteristics of sprouting and regeneration.

(2) Dynamic investigation of sprouting strips: the sprouting strips of different damaged types of Schima superba were investigated and measured in the middle of October (when the sprouting branches stopped growing). Record the dynamic information such as survival number, survival position and growth of the remaining shoots.

The inventor's practice research for many years found that: 3 main damaged Schima superba individuals sprouted rapidly and massively after the disaster, so as to maintain the necessary "resident niche" for individual survival; after the disaster (2008), the vitality of newly sprouted branches was relatively strong. With the increase of recovery process, the number of budding shoots of damaged Schima superba decreased rapidly, and the dynamic changes of death and survival of different damaged types were different. In the first three years after the snow and ice disaster, the average sprouting number of budding shoots of Schima superba individuals was significantly different between individuals with broken tips and individuals with double pockets (p<0.001). In the 6th year after the disaster (2013), the total number of individual shoots of the three kinds of affected trees tended to be the lowest and reached a stable level, accounting for 13.28% ~ 23.42% of the total number of shoots in the year after the disaster (2008).

Therefore, how to reasonably utilize and manage sprouting strips before their death, especially the utilization and growth promotion methods of newly sprouting strips in the year after the disaster, can obviously promote the recovery time of secondary forest after the disaster and the ecological effect.

Specifically, the tending management steps of 3 different damaged types of sprouting strips in step S5 include: (1) Tending management of broken shoots: aiming at the broken shoots of Schima superba after the disaster, thin shoots sprouted at the base of the trunk and the middle and lower parts of the trunk should be promptly removed, and 2-3 thicker shoots at the top of the trunk canopy should be kept, so as to remove the excess shoots at the top as much as possible, and keep the growth advantage of the top of the broken shoots while reducing the competition of nutritional 44 resources, SO as to promote the recovery.

(2) Tending and management of Schima superba: according to the occurrence and survival law of Schima superba, thinning measures were adopted for Schima superba's sprouting strips from the 3rd year after the disaster, before the autumn sprouting. The middle and upper parts of the trunk were removed, and the young sprouting strips were kept, while the thicker sprouting strips at the base of the trunk were kept, so as to reduce the competition of nutrition resources and promote the growth of sprouting strips and the survival and recovery progress of Schima superba.

(3) Inclined wood tending management: starting from the 3rd year after the disaster, the young sprouting strips of the trunk are removed, and the thicker sprouting strips in the middle and upper part of the trunk are kept.

(4) Different types of damage try to keep the new sprouting strips in the year and 2 years after the disaster, and promote germination and rejuvenation.

(5) It 1s considered that the final fate of the late-stage rump is dead wood, so in the 3rd year after the disaster, that is, during the canopy restoration of the secondary forest, the section of the trunk far from the base of the trunk of Schima superba should be cut down in time to make full use of the development needs of firewood or fungi of local mountain people. Try to keep the trunk section at the lower part of the trunk of Schima superba to maintain the normal growth of the sprouting branches at the base.

According to the invention, through the sprouting management of damaged trees in the early post-disaster period, including thinning of sprouting number and selection of sprouting position, the natural resources of damaged trees in the forest stand are fully utilized, the competitive pressure of broken-tipped trees on nutrient resources of broken-tipped trees is slowed down, the broken-tipped trees with low damage degree are promoted to recover as soon as possible, the crown structure before the disaster is formed, and the recovery of maximum carbon fixation capacity is realized.

The technical scheme of the present invention will be further described in detail with the following specific embodiments, including but not limited to the following embodiments.

Embodiment 1 Method for promoting recovery and management of secondary forest damaged by disturbance after snow and ice disaster by updating Schima superba sprout Implementation site: Schima superba is the main subtropical evergreen secondary forest in Jianglangshan Nature Reserve, Zhejiang Province;

Experimental area: 15 hectares Secondary forest stand density is 100 plants/mu -380 plants/mu 7902248 Slope: north slope, southwest slope and west slope.

Slope: 25-30 degrees Altitude: 400m-1500m Average annual rainfall: 1820mm Average annual temperature: 17.1°C The area has four distinct seasons, humid climate and abundant sunshine.

Composition of forest vegetation: The affected area is subtropical natural secondary forest, with a forest coverage rate of 67.1%. There are 4 groups, 7 classes and 15 formations of natural vegetation, including evergreen broad-leaved forest, coniferous and broad-leaved mixed forest, coniferous forest and shrub.

The experimental site is the northern slope of Jianglangshan National Scenic Spot in Shimen Town, Jiangshan City, Zhejiang Province. The slope is relatively flat, with a gradient of about 28 ~ 32°, an altitude of 350 ~ 500m and a soil of 70 ~ 100 cm deep in red loam.

The Schima superba forest, Pinus massoniana forest, Cunninghamia lanceolata forest, Phyllostachys pubescens forest, secondary shrubs and other vegetation types are mostly distributed below 900m above sea level. The main tree species of damaged secondary forest in the region are Cunninghamia lanceolata, Pinus massoniana, Castanopsis sclerophylla, Castanopsis fabri Hance, Cyclobalanopsis glauca (Thunberg) Oersted, etc. However, except for Schima superba, Cunninghamia lanceolata and Pinus massoniana, whose important values are greater than 10.0, all other broad-leaved trees are less than 5.0. Therefore, considering the important values, damage rates and the composition of important fire-resistant tree species, the germination and regeneration characteristics of Schima superba were studied emphatically.

Main damaged trees: Schima superb; Types of damage: 8 kinds, namely, undamaged, dead, uprooted, tilting, bending, broken tip, broken branch and trunk; Main types of damage: 3 kinds, namely broken-tip wood, turned-over wood and inclined wood; Among all the damaged types, Schima superba (45.45+2.11%) is affected by broken-tip wood, followed by tipping wood and inclined wood (28.41+235%and 12.51+4.88% respectively).

Individual survey of fixed samples: after the snow and ice disaster in 2008, the selected fixed samples were listed 1 time in mid-October, 2008, and then the listed samples were surveyed 1 time every year after the disaster, and the basic disaster background data such as the damaged type, DBH, basal diameter, tree height, crown width, and the inclination angle, slope position and slope direction formed by the damaged trunk and the original trunk before the disaster were recorded. Hobzzad Investigation of sprouting branches: The sprouting branches of different damaged types of Schima superba were followed up for 10 consecutive years (from 2008 to 2018), and the annual investigation was conducted in the middle of October (when sprouting branches stopped growing). In mid-October, 2008, all the sprouting branches of the listed sample plants were marked 1 times at first.

(1) Tending management of broken shoots: aiming at the broken shoots of Schima superba after the disaster, thin shoots sprouted at the base of the trunk and the middle and lower parts of the trunk should be promptly removed, and 2-3 thicker shoots at the top of the trunk canopy should be kept, so as to remove the excess shoots at the top as much as possible, and keep the growth advantage of the top of the broken shoots while reducing the competition of nutritional resources, so as to promote the recovery.

(2) Tending management of Schima superba: according to the occurrence and survival law of Schima superba, thinning measures should be taken from the 3rd year after the disaster, before the autumn germination, and the middle and upper parts of the trunk should be removed to keep the young shoots, while the thicker ones at the base of the trunk should be kept to reduce the competition of nutrition resources and promote the growth of the later shoots and the survival and recovery progress of Schima superba.

(3) Inclined wood tending management: starting from the 3rd year after the disaster, the young sprouting strips of the trunk are removed, and the thicker sprouting strips in the middle and upper part of the trunk are kept.

(4) Different types of damage try to keep the new sprouting strips in the year and 2 years after the disaster to promote germination and rejuvenation.

(5) It is considered that the final fate of the late-stage rump is dead wood. Therefore, in the 3rd year after the disaster, that is, during the canopy restoration of the secondary forest, the section of the trunk far from the base of the trunk of Schima superba should be cut down in time, so as to make full use of the development needs of local villagers for firewood or fungi, and the output of fuelwood per unit area in the post-disaster recovery stage of the secondary forest can be 2.9 t-ha”.

If 3 years after the disaster, the budding branches of the tree are not cut and utilized in time, with the natural recovery, the sprouting branches will obviously self-thinning, and a large number of sprouting branches will naturally die, eventually some individuals of the tree will die. And after a long-term recovery, the biomass of budding branches of Schima superba always kept a stable level, that is, the average biomass of budding branches per plant was 3.2 kgs per plant,

which increased slowly. Secondly, with the natural recovery, along with the phenomenon of self- thinning, it also produces resource competition for the recovery of broken-tip trees. 7902248 According to the invention, through timely thinning of the sprouting strips at the top of the broken-tip trees, the tree height of the broken-tip trees can be quickly recovered, and the height of the trees can be increased by 1.9 me trees ! in 3 years after the disaster, and the recovery height of the tree height can reach 7.0 me trees! on average; The total biomass carbon of its sprouting branches and leaves can reach 1.94 t-ha', the annual net carbon sequestration can reach 0.82 t-ha'-a’!, and the total biomass carbon value of sprouting branches and leaves can reach 5.76 t-ha! after 10 years. If the top sprouting strips of broken-tip trees are not thinned in time, the number of sprouting strips at the top is 4-5 trees ! on average, and there is a multi-head phenomenon. The top dominance is not obvious, and the rough growth and high growth of sprouting strips slow down. The tree height increases by 0.7-0.8 me trees! in 3 years after the disaster, and the average height of tree height recovery reaches 5.2 me trees.

The above are only the preferred embodiments of the present invention, and it should be pointed out that for those of ordinary skill in the technical field, without departing from the principle of the present invention, several improvements and embellishments can be made, and these improvements and embellishments should also be regarded as the protection scope of the present invention.

Claims (10)

1. A tending method for recovering subtropical secondary forest is characterized by oo comprising the following steps: distinguish different damaged types of individual trees, and count the individual distribution density and proportion of different damaged types of trees in the stand; according to the ranking of the highest proportion of damaged types, the important value of damaged trees and the proportion of their distribution, determine the main damaged trees and the main damaged types; based on the sprouting rate and living change annually of individuals with different damaged types, the tending management of main damaged trees was carried out.

2. The tending method according to claim 1 is characterized in that the different types of damage are undamaged, dead, rummaged, inclined, bent, broken tip, broken branch and dried.

3. The tending method according to claim 1 is characterized in that the main damaged trees are Schima superba, and the main damaged types of Schima superba are broken-tip trees, turned- over trees and inclined trees.

4. The tending method according to claim 1 is characterized in that, aiming at the broken-tip trees, small sprouting strips sprouted at the base of the trunk and the middle and lower parts of the trunk are promptly thinned, 2-3 thicker sprouting branches at the top of the trunk canopy are kept, and excess sprouting branches at the top are removed.

5. The tending method according to claim 1, characterized in that, from the 3rd year after the disaster, before the germination in autumn, the young sprouting strips in the middle and upper part of the trunk are removed, and the thicker sprouting strips in the base of the trunk are kept.

6. The tending method according to claim 1 is characterized in that, for the inclined trees, from the 3rd year after the disaster, the young sprouting strips of the trunk are removed, and the thicker sprouting strips in the middle and middle upper part of the trunk are kept.

7. The tending method according to claim 1 is characterized in that the new sprouting strips of the year after the disaster and the 2 year after the disaster are reserved for different types of damage, so as to promote germination and rejuvenation.

8. The tending method according to claim 1 is characterized in that, in the 3rd year after the disaster, that is, during the canopy restoration of the secondary forest, the trunk section far from the base of the trunk is cut off in time, and the trunk section at the lower part of the trunk of the tree is kept.

9. The tending method according to claim 1, characterized in that the dynamic monitoring method of sprouting rate and living change annually includes: at the end of the growing season, respectively measuring the number and location of sprouting at the first time after the disaster according to the damage type, repeating the above index monitoring every year, calculating sprouting rate and survival dynamics of different damaged types, and evaluating sprouting, 50224 renewal and recovery of different damaged types of trees according to the changes of sprouting rate and survival dynamic indexes of damaged types.

10. The tending method according to claim 9, characterized in that the sprouting rate (%) = the number of newly sprouted sprouts per year/the total number of existing sprouts in the trunk * 100%; The dynamic calculation of sprout survival is expressed according to the ratio of the number of existing sprouts in each year to the total number of sprouts in the previous year.