Patent Description:
At present, a major problem in forestry throughout Europe is the increased incidence of bark beetle - in particular, spruce bark beetle - in forests, which causes considerable damage to forestry. Bark beetle-infected trees need to be processed as soon as possible; and timely and effective decontamination of the infected wood is one of the most important activities. The methods of decontamination can be divided into manual, i.e. mechanical decontamination which mainly consists in debarking using a scraper or debarking by means of an adapter - a milling cutter - for a chainsaw. For machine debarking, a harvester with a debarking head is used or debarking is performed only in the wood storage. A specific problem is the protection of the wood stored in the forest. The following methods are currently available: classical spraying treatment of the debarked wood, covering of the wood with a foil, or covering of the wood with insecticidal nets.

The mechanical decontamination by manual debarking with a scraper is highly effective, achieving virtually <NUM>% efficiency. But it is very laborious. The complete surface of the tree trunks must be debarked, hence it is necessary to turn them around during debarking. This method is not applicable if pupae already begin to appear under the bark. Even the previously recommended methods - raking the scraped bark and subsequently burning it, performing the debarking on a foil, have virtually no effect in such situation.

Manual debarking with a chainsaw cutter is more effective than manual debarking with a scraper. The use of a harvester with a debarking head is most effective.

Another option is transport of the wood to a warehouse and subsequent processing, which may also include debarking. This method has its risks, for example, when the wood is transported in a stage of an almost adult bark beetle that can attack forests along the transport route.

The removal of infected wood (timber) without decontamination is inadmissible. Chemical decontamination consists mainly in manual spraying using various types of manual spraying devices. Such methods are slow, and represent a significant health risk for the spraying machines operators and can also have the result that more pesticide is spread on the treated wood or its surroundings, thus releasing more pesticide in nature than is actually required or desired. To be truly effective, the spraying must be done in time, at the latest at the pupae stage. If the decontamination is performed just before the bark beetles leave the wood, its effect is very fast, almost instantaneous. With increasing time between treatment and this last stage of development of the beetle, the rate of action slows.

Decontamination of stored wood is a very specific problem at present. Each tree trunk should be individually treated prior to storing, and after a period of time the treatment should be repeated or the wood should be removed from the forest. However, the current technologies do not treat each tree trunk individually, they usually involve spraying or covering of a whole pile of logs.

Another option is to protect the stored wood with an airtight foil. The wood is stacked on the foil, then it is covered by the foil (two layers of the foil are recommended) and the joints must be welded. Oxygen under the sail is consumed in a short time and replaced by carbon dioxide, which not only preserves the wood, but also causes the beetles to die, because they have nothing to breathe. This method has been used to protect wood from fire without any deterioration in wood quality even after several years of storage, but in principle it can also be used as a decontamination method. The disadvantage is that even minor damage to the foil can lead to introduction of oxygen under the sail and the protection ceases to function.

Thus, the methods available currently for protection of forests against bark beetle, especially for protection against bark beetle in forests where felled wood is stored, have a low reliability or represent health hazards for the workers.

Moreover the above describes techniques and methods of treatment signficantly increase the cost of wood processing, which is particularly harmful at a time when wood prices are severely depressed because of the beetle contamination, and when forestry managers need to dedidate as much financial resources as possible to the reconstruction of damaged forests.

Documents <CIT>, <CIT> and <CIT> disclose devices for processing felled trees, based on forestry vehicles.

In order to solve the above mentioned problems, the present invention provides an attachment for a forestry vehicle according to claim <NUM> which is useful for pesticidal treatment of wood of cut trees, as well as a forestry vehicle according to claim <NUM>.

In a first aspect of the invention, the attachment for a forestry vehicle comprises at least two nozzles, wherein each nozzle is provided with means for fixing the nozzle to a head of the forestry vehicle, and each nozzle is provided with a protective housing. The attachment further comprises at least one main tank for holding a liquid, a tubing connecting the main tank with the said nozzles, and a means for propelling the liquid from the tank to the nozzles and out of the nozzles.

The attachment further includes a head which is equipped with means for moving the tree trunk along its longitudinal axis. The attachment is suitable for being attached to any forestry vehicle (preferably heavy forestry vehicle) to which the head can be mounted. The head contains diameter sensors to measure the diameter of the tree trunk and the attachment is configured to adapt the number of active nozzles in response to the signal from the diameter sensors.

Thus, the attachment comprises a head attachable to a movable arm of a forestry vehicle, said head having means for gripping the three trunk and moving the tree trunk along its longitudinal axis, and said head being provided with at least two nozzles, wherein the nozzles are configured to cover the whole circumference or the whole surface of the tree trunk by a liquid sprayed through the nozzles. Each nozzle is provided with a protective housing. The attachment further comprises at least one main tank for holding a liquid, a tubing connecting the main tank with the said nozzles, and a means for propelling the liquid from the tank to the nozzles and out of the nozzles.

In a second aspect of the invention, a forestry vehicle is provided, said forestry vehicle comprising a head attached to a movable arm of the forestry vehicle, said head having means for gripping the three trunk and moving the tree trunk along its longitudinal axis, and said head being provided with at least two nozzles, wherein the nozzles are configured to cover the whole circumference or the whole surface of the tree trunk by a liquid sprayed through the nozzles. Each nozzle is provided with a protective housing. The forestry vehicle further comprises at least one main tank for holding a liquid, preferably disposed on the frame of the forestry vehicle, a tubing connecting the main tank with the said nozzles, and a means for propelling the liquid from the tank to the nozzles and out of the nozzles. The head contains diameter sensors to measure the diameter of the tree trunk and the forestry vehicle is configured to adapt the number of active nozzles in response to the signal from the diameter sensors.

The forestry vehicle may be a harvester, a forestry machine, a forestry tractor, or any other machine used for felling and/or bucking and/or manupulating tree trunks. Most typically, the forestry vehicle is a harvester.

In this text, the term "harvester" or "forestry harvester" is intended to mean a type of heavy forestry vehicle for cut-to-length logging operations for felling, delimbing and bucking trees.

The nozzles are configured to cover the whole circumference or the whole surface of the tree trunk by a liquid sprayed through the nozzles. In a preferred embodiment, the nozzles are fixed to the head and distributed in regular intervals around an opening formed by the gripping and moving means.

The at least two nozzles are thus preferably disposed or configured to be disposed in regular distances along the circumference of the opening through which the tree trunk moves when the apparatus of the invention is in use. The opening is typically formed by the gripping and moving means. The nozzles are disposed so that they allow a regular and complete spraying of the tree trunk around its circumference.

"Regular distances" or "regular intervals" are intended to mean distances between neighbouring (adjacent) nozzles which are substantially equal. By "substantially equal" it is understood that that the distances between neighbouring nozzles differ by no more than <NUM> %, preferably by no more than <NUM> %, more preferably by no more than <NUM> %.

The number of nozzles may vary. For example, two nozzles, three nozzles, four nozzles, five nozzles, six nozzles, seven nozzles, eight nozzles, nine nozzles, ten nozzles may be provided. Even numbers of nozzles are preferred.

For thinner tree trunks, two nozzles may suffice; for thicker tree trunks, three, four, five, six, or more nozzles may be provided.

The nozzles may typically be disposed on jaws of delimbing means, on the frame of the means for gripping and moving the tree trunk, or on separate jaws or holder(s) which are attached to the head and arranged so that the nozzles are disposed in regular distances around the circumference of the opening through which the tree trunk moves when the head is in use.

The nozzles may in some embodiments be arranged substantially circularly around the opening through which the tree trunk moves when the head is in use. The nozzles are arranged in regular distances so that they can reliably cover the whole circumference of the tree trunk by the sprayed liquid.

The nozzles preferably have a spraying angle within the range from <NUM> to <NUM> degrees, more preferably from <NUM> to <NUM> degrees. The setup of the nozzles within the said spraying angle ensures that all or almost all the sprayed liquid is applied on the tree trunk. Generally, the closer to the moving tree trunk the nozzles are disposed, the wider spraying angle is needed, and vice versa - the farther from the moving tree trunk the nozzles are disposed, the narrower spraying angle is sufficient. This results in significant savings of the spraying liquid which translate into a higher economic effectiveness, and it prevents undesirable splashing of the insecticide contained in the spraying liquid to the surrounding environment where it could kill non-target insects.

The fixing means may be any means suitable for fixing the nozzles to the head or to a component of the head. In particular, the fixing means may be screws, anchors, brackets, clamps, welds, It is particularly advantageous when the nozzles are disposed within recesses or cavities provided on/within the component of the head to which the nozzles are fixed (e.g., delimbing jaws, frame of the gripping and moving means, drive rollers, drive roller housings). When the head is in use and delimbing the tree, the nozzles risk being damaged by the branches and other pieces of wood flying around. Their disposal within recesses increases the protection of the nozzles and decreases the risk of their damage. Recesses and cavities are considered in this text as a type of protective housing, i.e., the term "protective housing" also includes recesses and cavities, and disposal of the nozzles within recesses and cavities.

Each nozzle is provided with a protective housing which may have any suitable form, such as, for example, the form of a recess, a cavity or a structure protruding outside and encompassing the nozzle and leaving just an opening for spraying the liquid. As described above, the nozzles are at a rather big risk of being damaged by branches or other pieces of wood flying from the delimbing jaws of the head, The protective housing provides the minimum necessary protection for the nozzles, and optionally to other components such as control valves, tubing, etc. The protective housing is typically metallic, and encloses the nozzle so that it does not prevent its spraying in the direction of the tree trunk being moved through the opening. The protective housing may in some embodiments be closable and openable. It may be opened when the spraying function is required, and it may be closed when the spraying function is not required, thus reliably protecting the nozzles. The closing and opening of the protective housing may be, for example, manually controllable, or electrically controllable.

The nozzles may be individually controllable. The supply of liquid to the nozzles may be controlled individually, e. g, by providing a control valve separately for each nozzle, or by providing a first control valve circuit for one half of the nozzles and a second control valve circuit for the other half of the nozzles, wherein the nozzles controlled by the first control valve circuit and the nozzles controlled by the second control valve circuit alternate. The control valves may be controlled by a liquid supply control unit which may be part of the control unit of the vehicle or it may be a separate unit. The amount of active nozzles may be adapted to the size of the treated wood piece. For example, the head may be provided with four nozzles which are all used for spraying thick tree trunks, but for thin tree trunks only every second nozzle is used, i.e., two nozzles. In another example, the head may be provided with six nozzles which are all used for spraying thick tree trunks, but for thin tree trunks only every second nozzle is used, i.e., three nozzles. This allows significant savings of the liquid used for spraying.

The nozzles may be provided with at least one non-return (one-way) valves. When the control valve closes, the non-return valve closes the nozzle and thus the liquid remains in the tubing and does not flow out of the nozzle. It is advantageous that the non-return valve(s) is/are as close to the nozzles as possible, because this decreases the amount of the liquid that flows out of the nozzle after the control valve is closed. The non-return valve(s) avoid unnecessary spilling of the spraying liquid.

In some embodiments, the nozzles may be attached movably on the head. Movable attachment of the nozzles allows for adjusting the nozzles to various lengths of the elongated wood pieces treated by the device of the invention. Movable attachment also allows the use of nozzles with a narrow spraying angle (e.g., up to <NUM> or up to <NUM> degrees), thus limiting the amount of the pesticidal liquid sprayed into the surrounding environment and limiting the damage to other insect species caused by this pesticidal liquid.

The movement of the nozzles may be performed using electromotors attached to the nozzles, for example, each nozzle may be provided with its electromotor, or two or three or more nozzles may be attached to one electromotor. The electromotors may be controlled by a nozzle movement control unit, for example based on the wood piece dimension data entered manually or electronically, or based on information available from sensors which may optionally be disposed on the head for measuring the wood piece dimensions.

The head contains means for moving the tree trunk. Such means typically are or contain at least two feed rollers. The feed rollers grasp the tree by being pressed against the tree trunk and move it by the rotational movement of the feed roller wheels.

The head typically contains a delimbing means which are used to cut branches off the tree trunk as it moves by the action of the gripping and moving means. The delimbing means typically contain or are jaws, and the jaws have at least one sharp edge, i.e., they serve as knives in the delimbing stage.

A typical head of a forestry harvester contains two feed rollers to grip and move the tree trunk through the head along its longitudinal axis (the feed rollers are an example of gripping and moving means), two or more curved delimbing knives for removing branches (an example of delimbing means), a chain saw to cut the tree at its base in the felling stage, and cut the trunk to length in the bucking stage. It may further contain diameter sensors to measure the diameter of the tree trunk, and a measuring wheel which measures the length of the step as it is fed through the head. The diameter sensors and the measuring wheel cooperate in known harvesters to calculate the volume of timber harvested.

The signal from the diameter sensors may be used in the present invention as an input information for controlling the number of active nozzles. Typically, this may be done by employing a simple algorithm which switches on the liquid supply only to every second nozzle (or only to the first control valve circuit or only to the second control valve circuit) when the trunk diameter is lower than (or equal to) a pre-determined threshold value, or switches on the liquid supply to all nozzles (or to both control valve circuits) when the trunk diameter is higher than (or equal to) a pre-determined threshold value.

The main tank has to have a large volume, corresponding to the spraying liquid to be consumed within, for example, one day. This may correspond to <NUM> to <NUM> liters, preferably <NUM> to <NUM> liters, or <NUM> to <NUM> liters, for example. It may be possible to suspend such large main tank from the vehicle frame, or to fix it to the vehicle frame; depending on the possible load of the vehicle frame. In some embodiments, a plurality of main tanks may be provided, wherein each main tank may be smaller, and their total volume may correspond to the herein mentioned volumes.

The spraying liquid (also called "liquid", "pesticidal liquid" in this disclosure) is a pesticide solution, dispersion or suspension. The choice of the pesticide depends on the target pest. When the target pest is an insect, the pesticide is an insecticide effective against the target insect species.

The present invention helps to reduce the amount of the spraying liquid needed for spraying. The automated, thorough, easily controllable and targeted spraying of only the tree trunk, and only when the tree is moved through the delimbing head, results in a more effective use of the spraying liquid and in virtually no spraying liquid misapplied to the surrounding environment, thus reducing the amount of the used spraying liquid.

The means for propelling the liquid may include a pump or a compressor, or any other suitable liquid-propelling means. The pump or the compressor or other liquid-propelling means may be driven electrically or hydraulically, or may be driven using the energy provided by the forestry machine engine. The embodiments containing a pump or a compressor are described herein as particular examples.

In some embodiments, the means for propelling the liquid may contain a pump connected to the main tank and a working tank connected with the pump, said working tank being equipped with at least one control valve for controlling the amount of liquid propelled through the nozzles. The presence of the control valve(s) allows to control and adjust the dosing of the liquid.

In some embodiments, the means for propelling the liquid may contain a working tank connected to the main tank for holding the liquid, preferably via a check valve, said working tank being connected via a valve to an airtank connected to a compressor, and said working tank being equipped with at least one control valve for controlling the amount of liquid propelled through the nozzles. The presence of the control valve(s) allows to control and adjust the dosing of the liquid.

The working tank is an auxiliary tank from which the liquid is propelled directly to the nozzles, wherein the amount of the liquid may be controlled by one or more control valves. The working tank is typically suspended from or fixed to the vehicle frame. The working tank contains the liquid under pressure, to be propelled under pressure to the nozzles. Typically, the working tank is provided with a valve for setting a pre-determined constant output pressure of the liquid outputted from the working tank, and the control valve(s) are typically disposed in the tubing between the said valve and the nozzles. The valve for setting a pre-determined constant output pressure ensures a constant pressure of the liquid which is further propelled to the nozzles as controlled by the control valves; thus ensuring a constant dosage of the liquid. This in turn further reduces the consumption of the spraying liquid.

The tubing may include tubes, e.g. flexible tubes, or pipes. The tubing must be liquidimpermeable, and it is preferably made of an inert material (e.g. plastics, rubber, non-corrosive metals such as steel). The tubing should be made of a durable and mechanically resistant material, i.e., preferably metals, or reinforced plastics or reinforced rubber, or should be protected against mechanical stresses and delimbed pieces of wood, e.g., by a housing.

The attachment and the forestry vehicle according to the present invention are particularly useful for protecting wood against pests, in particular against bark beetle, and/or for killing pests (in particular bark bettle) present on the tree trunks.

Furthermore, the present invention provides a method for protecting forests against pests, in particular against bark beetle, which comprises the steps of.

Using this method, the trees surrounding the place where the wood is stored are protected from further spreading of the pest from the felled infected trees.

"Harvesting of wood" or "harvesting of trees" includes any or all of the steps of cutting the tree, delimbing the tree, bucking the tree, storing the logs.

The invention is further explained using a particular embodiment of the invention, as shown in the figures. The example and the figures shall not be construed as limiting the scope of the invention which is exclusively determined by the claims.

In the particular embodiment of the invention, <FIG> shows a forestry vehicle <NUM> with an attachment according to the invention. The vehicle comprises a head <NUM> disposed on a movable arm <NUM>. The head is represented very schematically, without any specific depiction of the gripping and moving means or the delimbing means. The arrangement of such gripping and moving means and delimbing means within the head is well known to a person skilled in the art. The head <NUM> is provided with four nozzles <NUM> arranged in regular distances around the opening of the head which is normally formed by the arrangement of the gripping and moving means. The opening of the head can receive a tree trunk <NUM>. The nozzles <NUM> are directed so as to cover the whole surface of the tree trunk <NUM> by sprayed liquid. The tank <NUM> for holding liquid (also called herein "main tank") is suspended on the frame <NUM> of the forestry vehicle <NUM>. The main tank <NUM> is connected with the nozzles <NUM> by a tubing <NUM>.

<FIG> shows an embodiment with six nozzles arranged regularly around the opening of the head.

Means <NUM> for propelling liquid is mounted on the frame <NUM>. The means <NUM> for propelling liquid may be constructed in various ways, two exemplary embodiments are shown in <FIG>.

<FIG> shows a scheme of one embodiment of the means <NUM> for propelling liquid, which contains a working tank <NUM> provided with a valve for setting the output pressure (not shown) and a pump <NUM> connected to the main tank <NUM>. Another control valve <NUM> controls the amount of the liquid supplied to the nozzles <NUM>.

<FIG> shows a scheme of another embodiment of the means <NUM> for propelling liquid, which contains a working tank <NUM> connected to the main tank <NUM> via a check valve <NUM>, and the working tank <NUM> is connected with an air tank <NUM> via a valve <NUM>, and the air tank <NUM> is in turn connected with a compressor <NUM>. The valve <NUM> ensures the correct filling of the working tank <NUM>, which is then connected with the control valve <NUM> for controlling the amount of the liquid supplied to the nozzles <NUM>.

The forestry vehicle <NUM> is preferably a harvester.

The treatment of a tree trunk using the herein described device proceeds as follows. The tree trunk <NUM> is gripped by the head <NUM>. Then pesticidal liquid from the main tank <NUM> is propelled by the liquid propelling means <NUM> to nozzles <NUM> via the tubing <NUM> and via at least one control valve <NUM>. In some embodiments, the supply of liquid to the nozzles <NUM> is controlled individually for each nozzle, or by two control valve circuits, each for one half of the nozzles, wherein the nozzles controlled by each circuit are alternating. In these embodiments, all four or only two nozzles <NUM> can be used, thus adapting to the thickness of the sprayed tree trunk.

Claim 1:
An attachment for a forestry vehicle for felling and/or bucking and/or manipulating tree trunks, wherein the said attachment comprises at least two nozzles (<NUM>) and a head (<NUM>) attachable to a movable arm (<NUM>) of a forestry vehicle (<NUM>),
wherein each nozzle (<NUM>) is provided with means fixing the nozzle (<NUM>) to the head (<NUM>), and each nozzle (<NUM>) is provided with a protective housing, wherein the attachment further comprises at least one main tank (<NUM>) for holding a liquid, a tubing (<NUM>) connecting the main tank (<NUM>) with the said nozzles (<NUM>), and a means (<NUM>) for propelling the liquid from the tank (<NUM>) to the nozzles (<NUM>) and out of the nozzles (<NUM>),
wherein the head (<NUM>) has means for gripping a tree trunk and moving the tree trunk (<NUM>) along its longitudinal axis,
wherein the nozzles (<NUM>) are configured to cover the whole surface of the tree trunk (<NUM>) by a liquid sprayed through the nozzles (<NUM>),
characterized in that the head (<NUM>) contains diameter sensors to measure the diameter of the tree trunk (<NUM>) and the attachment is configured to adapt the number of active nozzles in response to the signal from the diameter sensors.