JP2023166767A - Young tree protective covering - Google Patents

Abstract

To provide a young tree protective covering capable of reducing a burden of an operator, and maintaining pest repellent effect, and biodegradable in the soil if left as is after the end of a usage period.SOLUTION: A young tree protective covering 10 includes a cylindrical film 16 mainly composed of cellulose acetate, having a closed cylindrical upper end 11 and an open cylindrical lower end 12, and provided with multiple vent holes 15 on a side peripheral surface, for covering a young tree 20 from above, a bearing bar 22 made of wood, supporting the cylindrical film 16 along a longer direction, and having one end fixed to the ground 21, and a biodegradable fastener 25 for fastening the cylindrical film 16 onto the bearing bar 22.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cover that protects young trees from being eaten by pests.

In recent years, the number of deer, antelopes, and hares has increased, and the damage caused by the core buds and new shoots of planted seedlings being eaten is increasing. Once the core bud of a young tree is eaten, the seedling's upward growth stops. The occurrence of such damage causes trees to become meaningless, leading to increased forestry production costs and a decline in forest owners' motivation to manage their forests.

Furthermore, in forests with high deer densities, most of the branches, leaves, and understory vegetation within reach of the deer's mouths have disappeared due to feeding damage, and the public functions of forests, such as preventing soil runoff, have declined. Put it away. To prevent such feeding damage to the core buds and shoots of young trees, protective measures have been taken, such as installing fences to widely surround the entire seedling with metal nets, plastic panels, or the like. However, this method had the problem that it was expensive and labor intensive, and it was not very effective as it could be destroyed by wind, snow, or animals.

On the other hand, for cypress and cedar, seedlings that are around 40 to 60 cm tall can grow to 140 to 160 cm in about three years after being planted. It is also known that if a young tree grows well to this point, there is no risk of the core bud at the top center being damaged by feeding. Based on such knowledge, a technique has been proposed to protect young trees from feeding damage by directly covering each young tree with a protective material for a relatively short period of 3 to 5 years (for example, Patent Documents 1 to 4) .

Japanese Patent Application Publication No. 2005-151862 Japanese Patent Application Publication No. 2010-239889 Japanese Patent Application Publication No. 2014-161308 JP2019-198247A JP2019-208487A

As protective materials for preventing feeding damage that have been proposed so far, there is a combination of a sheet-like material made of fiber or net and an animal repellent. However, since protective materials made of such materials are bulky and heavy, there is a problem that the work burden of carrying them to mountains and forests becomes heavy. Furthermore, the burden of collecting and disposing of used protection materials after the protection period for young trees ends is also a heavy task. Another problem with animal repellents is that they cannot maintain their effectiveness over the growth period of young trees.

On the other hand, in order to eliminate the work burden of collecting and disposing of used protective materials, it has been proposed that the protective materials be made of biodegradable resins such as polylactic acid, allowing them to be disposed of while being left on site. . However, polylactic acid has low soil biodegradability and low marine biodegradability, so its effectiveness is questionable.

The present invention was developed in consideration of these circumstances, and provides a cover for protecting young trees that reduces the burden on workers, maintains its pest repellent effect, and biodegrades in the soil when left alone after the period of use. The purpose is to provide

The young tree protective cover according to the present invention is a cylindrical film that is made of cellulose acetate as a main component, has a closed cylindrical upper end, an open cylindrical lower end, and has a plurality of ventilation holes on the side circumferential surface, and is placed over a young tree from above. a support rod made of wood that supports the cylindrical film along its length and has one end fixed to the ground; and a biodegradable fastener that fastens the cylindrical film to the support rod. There is.

The present invention provides a protective cover for young trees that reduces the burden on workers, maintains the effect of repelling pests, and biodegrades in the soil when left as is after the period of use.

(A) XY top view, (B) XZ side view, and (C) YZ side view of the young tree protection cover according to the embodiment of the present invention.

(First embodiment)
Embodiments of the present invention will be described below based on the accompanying drawings. FIG. 1(A) is an XY top view of a young tree protection cover 10 according to an embodiment of the present invention. FIG. 1(B) is an XZ side view of the young tree protection cover 10. FIG. 1(C) is a YZ side view of the young tree protection cover 10.

In this way, the young tree protection cover 10 is made mainly of cellulose acetate, has a cylindrical upper end 11 closed, a cylindrical lower end 12 open, and has a plurality of ventilation holes 15 on the side circumferential surface, so that the young tree 20 can be protected from above. A cylindrical film 16 to be covered, a support rod 22 made of wood that supports the cylindrical film 16 in the longitudinal direction and has one end fixed to the ground 21, and a biodegradable cylindrical film 16 that is fastened to the support rod 22. A fastener 25 is provided.

The cylindrical film 16 is made by cutting a continuous cylindrical body whose main component is cellulose acetate in the length direction, leaving the opening at the lower end 12 of the cylindrical shape as it is, and the opening at the upper end 11 of the cylindrical shape by heat sealing or adhesive film. It is closed with etc. Alternatively, the cylindrical film 16 may be made into a cylindrical shape by pasting together the overlapping portions of rolled flat films, and the opening at the cylindrical lower end 12 may be left as is and the opening at the cylindrical upper end 11 may be closed by heat sealing.

Since the growth of the young tree 20 is relatively fast, the support rod 22 is made of a square lumber made by cutting natural wood such as cedar. The appropriate length of the support rod 22 is about 50 cm added to the length of the cylindrical film 16 for fixing it to the ground 21. Furthermore, a preservative is applied to the portion of the support rod 22 buried in the ground 21 to prevent corrosion in the soil. Further, the number of support rods 22 is not limited to one as shown in the figure, and two support rods may be used to sandwich the cylindrical film 16 along the longitudinal direction. At this time, both ends may be fixed to the ground 21, or only one end may be fixed.

As shown in the figure, the fastener 25 may be a dowel that is inserted into a hole provided in the support rod 22 and brings the cylindrical film 16 into close contact with the support rod 22 with a flange body, or it may be a dowel that is inserted into a hole provided in the support rod 22 and allows the cylindrical film 16 to be tightly attached to the support rod 22 from above the cylindrical film 16. It may be a binding band (not shown) that wraps around the two to bring them into close contact. Note that the fastener 25 may be employed without particular limitation as long as it has the function of fastening the cylindrical film 16 to the support rod 22.

Furthermore, the young tree protection cover 10 includes a fixing stake 26 that fixes a part of the cylindrical lower end 12 of the cylindrical film 16 to the ground 21. By fixing the cylindrical lower end 12 with the fixed stake 26, the cylindrical film 16 is prevented from being turned up due to weather phenomena such as wind and rain or the growth of the young tree 20, or from being broken due to overload. .

The above-described fasteners 25 (such as cable ties) and fixing stakes 26 are made of a biodegradable material, and are preferably injection molded products made of a material whose main component is cellulose acetate. Alternatively, the fasteners 25 (such as dowels) and the fixed stakes 26 may be made of wood.

To install the young tree protection cover 10, a hole with a diameter of 10 cm and a depth of about 50 cm is made in a suitable ground 21 at the planting site of the young tree 20, a support rod 22 is inserted, and the hole is fixed with earth and sand. Then, the supporting rod 22 is covered with the cylindrical film 16 so that the entire young tree 20 is accommodated inside. Then, the support rod 22 and the cylindrical film 16 are fixed at necessary locations using fasteners 25.

Further, the cylindrical lower end 12 of the young tree protection cover 10 is expanded and fixed to the ground 21 with a fixing stake 26. At this time, when viewed from above (FIG. 1A) of the young tree protection cover 10, the support rod 22 and the fixed stake 26 are arranged so as to face each other across the edge of the heat-sealed cylindrical upper end 11. Therefore, a sufficient free space necessary for the growth of the young tree 20 is secured inside the cylindrical film 16.

The cylindrical film 16 has a height of 1 to 2 m, a width of 30 to 50 cm, and a film thickness of 50 to 200 μm. As shown in the figure, the cylindrical film 16 is linearly fixed along the longitudinal direction by the support rod 22, and other parts are not fixed. Therefore, due to wind or the like, friction noise is generated between the cylindrical films 16 or between the cylindrical films 16 and the young trees 20. This fricative sound has a repellent effect on animals with sensitive hearing.

The ventilation holes 15 provided in the cylindrical film 16 are circular with a diameter of 20 to 30 mm, and occupy an area of 10 to 30%. This ensures ventilation and lighting in the inner space of the cylindrical film 16 in which the young tree 20 is accommodated. The ventilation holes 15 are provided using a punching mold, and the optimum diameter and number are determined depending on the type of young tree 20 and the situation of the area where the tree is planted.

The cylindrical film 16 may be made of a single layer of film, or may be a laminate of two or more layers of films. Furthermore, the cylindrical film 16 may be a laminate of a cellulose acetate film layer and a biodegradable film layer other than cellulose acetate.

A plurality of cylindrical films 16 are continuously supplied in a roll shape so as to be separated from each other at perforations. Since the plurality of cylindrical films 16 are roll-shaped continuous bodies in this way, even if they are produced in large quantities, they are not bulky and lightweight, and can be easily transported to mountains and forests. Additionally, the perforations allow the tubular film 16 to be separated from the roll one by one at the tree planting site, contributing to improved work efficiency.

The cylindrical film 16 of cellulose acetate is molded using a general inflation film molding machine at a molding temperature of 230° C. or lower. The heat-sealing process of the cylindrical upper end 11 of the cylindrical film 16, the punching process of the ventilation holes 15, and the perforation process can be performed at the time of film molding. Alternatively, continuous processing can be performed during bag-making processing of roll film. Moreover, the cylindrical film 16 can also be molded using a T-die film molding machine in addition to the inflation film molding machine. In addition, regardless of which film forming machine is used, by forming the film without stretching, the cylindrical film 16 does not spread according to the size of the young tree 20 and hinder the growth of the young tree 20. is obtained.

Cellulose acetate is a semi-synthetic polymer obtained by esterifying cellulose with acetic anhydride, and is broadly classified into two types depending on the degree of acetylation. The first is cellulose triacetate (CTA) with a degree of acetylation of 59% or more, and the second is cellulose diacetate (CDA) with a degree of acetylation of about 50 to 59%. Cellulose acetate is biodegradable, and has particularly excellent soil biodegradability and marine biodegradability, so it has recently been in the spotlight from the perspective of the global environment.

Cellulose acetate maintains sufficient properties such as weather resistance, tensile strength, and surface smoothness for several years during the growth period of young trees 20. After the growing period ends, the used young tree protection cover 10 will biodegrade in a relatively short time if left in the forest, and will also take a relatively short time even if it flows into the ocean via rivers etc. It biodegrades in the ocean. Furthermore, cellulose acetate has a distinctive acetic acid odor, which has the effect of deterring deer, serows, hares, etc. who have a sensitive sense of smell.

A typical cellulose acetate molded article is obtained by fluidizing a cellulose acetate solution dissolved in a solvent into a desired form, and then removing the solvent by evaporation or the like. The cylindrical film 16 applied in this embodiment is made of cellulose acetate pellets filled with a plasticizer in a range of 10 to 30% by weight by a compounding method to give it thermoformability, instead of using such a solvent method. The film is formed using a standard method.

Examples of plasticizers include glycerin triacetate compounds (triacetin), adipic acid ester-containing compounds, adipic acid polyester-containing compounds, polyether ester compounds, sebacic acid ester compounds, epoxy esters, benzoic acid esters, trimellitic acid esters, and glycol ester compounds. , acetate ester, dibasic acid ester compound, phosphate ester compound, phthalate ester compound, camphor, citric acid ester, stearic acid ester, metal soap, polyol, polyalkylene oxide and the like. Among these, adipate ester-containing compounds, polyether ester compounds, and non-phthalic acid compounds are preferred, and adipate ester-containing compounds are more preferred.

The adipate ester-containing compound (compound containing an adipate ester) refers to a compound containing an adipate ester alone, or a mixture of an adipate ester and a different compound. Examples of the adipic acid ester include adipic diester, adipic acid polyester, and the like.

Examples of non-phthalic acid compounds include benzyl butyl phthalate (BBP), bis(2ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), and the like.

The solubility parameter (SP value) of the polyether ester compound is preferably 9.5 or more and 9.9 or less, more preferably 9.6 or more and 9.8 or less. When the solubility parameter (SP value) is set to 9.5 or more and 9.9 or less, the dispersibility in the cellulose acetate derivative is improved.

A white pigment is blended into the cellulose acetate so that the transmittance of visible light defined by wavelengths from 380 nm to 780 nm is 20% to 40%. If the visible light transmittance is less than 20%, sunlight exposure may be insufficient and the young tree 20 may suffer from poor growth. Moreover, if the transmittance of visible light exceeds 40%, the young tree 20 will be visible through the young tree protection cover 10.

Pests such as deer and black bears have excellent senses of smell and hearing, but are said to have poor eyesight. Also, while the retina of the human eye has three types of cones and allows us to see three colors, the retinas of these pests have only two types of cones, so they are said to have dichromatic vision.

In this way, since cellulose acetate contains a white pigment and a light scattering agent, most of the sunlight that enters the young tree protective cover 10 is diffusely reflected on its surface. This further improves the visibility of the young tree protective cover 10 for many pests that have dichromatic vision, giving them a sense of repulsion. Examples of such white pigments include rutile titanium oxide, anatase titanium oxide, zinc white, barium sulfate, calcium carbonate, magnesium oxide, lithopone, lead white, and the like.

In addition to the above-mentioned plasticizer and white pigment, cellulose acetate may also contain an inorganic filler, an organic filler, and an additive.

Next, an example in which the effects of this embodiment were confirmed will be described.
The cellulose acetate material used was a commercially available product with a degree of acetylation of 55%. For 100 parts by weight of a mixture of cellulose acetate material and plasticizer (triacetin) mixed at a weight ratio of 73:27, 0.6 parts by weight of rutile titanium oxide as a white pigment and 0 parts by weight of a general antioxidant. .6 parts by weight and 0.6 parts by weight of a common weathering additive.

(Manufacture of pellets of cellulose acetate composition)
A mixture of the cellulose acetate material and the plasticizer (triacetin) is produced by mixing the cellulose acetate material with stirring while spraying the plasticizer in a high-speed mixer set at 500 rpm/min. Further, using a ribbon blender, which is a low-speed mixer set at 120 rpm/min, a white pigment, an antioxidant, and a weather-resistant additive were blended.

As a kneading machine, a twin-screw extruder CK70HT (screw diameter 70 mm, L/D=44) manufactured by Taiwanese manufacturer CKF was used. The screw rotation speed was set at 300-600 rpm, and the molding temperature was 200-220°C. Then, the kneaded body discharged from the kneader was formed into pellets.

(Inflation film molding process)
The results of further processing the molded pellets into a blown film will be explained. The molding machine into which the pellets were introduced was a single-layer blown film molding machine manufactured by Placo Co., Ltd., and the screw diameter was set to 50 mm and the circular die width was set to 100 mm. The molding conditions were a molding temperature of 220 to 225°C, a blow ratio of 1.5 to 2.0, a film shape of 400 mm in width and 100 μm in thickness, and a winding speed of 2 to 5 m/min.

The bubbles of the formed blown film were stable, and continuous molding and uniform film thickness were possible. By adjusting the conditions, the film thickness could be arbitrarily varied from 30 to 150 μm, and roll winding was also possible.

(Visibility evaluation)
Visibility was evaluated by the light transmittance of the molded film. The film was cut into a size of 50 mm in the MD direction x 50 mm in the TD direction, and using a spectrophotometer (model number: "SE7700", manufactured by Nippon Denshoku Industries Co., Ltd.), light was transmitted from a wavelength of 380 nm to 780 nm at a scanning period of 5 nm. The rate was measured. As a result, the transmittance was in the range of 20% to 40%.

(Biodegradability evaluation)
Biodegradability evaluation is performed to ensure that the formed film complies with standard requirements such as ISO 17556 "Aerobic biodegradability test in soil" and ISO 23977 "Plastics - Determination of aerobic biodegradation of plastic materials exposed to seawater" It was confirmed through testing by an external specialized organization that the product satisfies the standards using the testing method described above.

According to the young tree protection cover of at least one embodiment described above, by covering the young tree with a cylindrical film made of cellulose acetate from above, the burden on the worker is reduced and the effect of repelling pests is improved. It lasts for a long time, and after the end of its usage period, it can be left as is to biodegrade in the soil.

DESCRIPTION OF SYMBOLS 10... Young tree protection cover, 11... Cylindrical upper end, 12... Cylindrical lower end, 15... Ventilation hole, 16... Cylindrical film, 20... Young tree, 21... Ground, 22... Support rod, 25... Fastener , 26...Fixed stake.

Claims (5)

A cylindrical film that is made of cellulose acetate as a main component, has a closed cylindrical upper end, an open cylindrical lower end, and has a plurality of ventilation holes on the side circumferential surface, and is placed over a young tree from above;
a support rod made of wood that supports the cylindrical film along its length and has one end fixed to the ground;
A young tree protection cover that is biodegradable and includes a fastener that fastens the cylindrical film to the support rod. The young tree protective cover according to claim 1,
The cylindrical film is a young tree protective cover in which a white pigment is blended with the cellulose acetate so that the transmittance of visible light defined by wavelengths from 380 nm to 780 nm is 20% to 40%. In the young tree protective cover according to claim 1 or claim 2,
The cylindrical film has a shape with a height of 1 to 2 m, a width of 30 to 50 cm, and a film thickness of 50 to 200 μm,
The ventilation hole provided in the cylindrical film is circular with a diameter of 20 to 30 mm, and the occupied area ratio is 10 to 30%. In the young tree protective cover according to claim 1 or claim 2,
The cylindrical film is a young tree protection cover in which a plurality of cylindrical films are continuously supplied in a roll shape so as to be separated from each other at perforations. In the young tree protective cover according to claim 1 or claim 2,
A young tree protection cover including a fixing stake that fixes a part of the cylindrical lower end of the cylindrical film to the ground.

Images