Askåterföring till skog, vardande blir verklighet?

• Askåterföring är ett medel för att långsiktigt kunna ta ut en stor mängd skogsbränslen utan att därför utarma marken. Projektet som avslutades med en rapport år 2004 är en systemstudie där hela kedjan från fjärrvärmeföretaget till den enskilda skogsägaren undersöks. Projektet har två huvudsyften, dels att undersöka och tydliggöra drivkrafter och hinder för askåterföring ur ett dynamiskt perspektiv, dels ge underlag för rekommendationer för den praktiska utformningen av olika askåterföringssystem. Fokus ligger på formella och informella institutioner, dvs. såväl på utformningen av olika lagar och regelverk som på aktörernas, i huvudsak bränsleanvändarnas, bränslemäklarföretagens och skogsägarnas attityder och erfarenheter. För att optimera de totala förutsättningarna och undvika ”närsynthet” präglas projektet av en systemsyn som sträcker sig från den primära askproducenten, värmeverket, till den slutlige askkonsumenten, skogsägaren. Den empiriska delen består av tre fallstudier av tre energiföretag, Växjö Energi AB, Borås Energi AB samt Falu Energi AB samt en enkät som besvarades av nära nog samtliga relevanta energiföretag i Sverige.

• Executive summary Ash recycling is a means to safe guard nutrient availability while harvesting forest fuels. Research on the consequences of ash recycling started in the end of the 1970’s, definite results were presented in 1996. The National Board of Forestry presented guidelines on ash recycling in 1999 and 2001. Yet, there has been no large scale application of the technology despite improved economic incentives. A waste tax which also applies to ash was introduced in 2000, it has been successively increased and today amounts to 370 SwCr/ton. This is a systems study of ash recycling where the whole chain from district heating utility to individual forest owner is investigated. Case studies of three district heating utilities, Växjö Energi AB, Borås Energi AB and Falu Energi AB, indicate that the utilities have, generally, been satisfied with their activities on ash recycling and see the investment constantly improving while the tax is increasing. A nation-wide questionnaire shows that the greatest impediments to ash recycling have been that managements miss clear-cut rules, have not been able to buy the service and generally considered that they lack knowledge. About a third of the utilities actively tried to identify other means of disposing of their ash. Main driving forces for ash recycling have been environmental concerns and to create immaterial values. Under these circumstances ash recycling may equal the deposition costs. Previous research has indicated that non-industrial private forest owners consider that nutrient loss may render the harvest of forest fuels problematic. Our study on forest owners show a great need for knowledge, the forest owner frequently indicates that he/she does not know sufficiently to be able to evaluate ash recycling. Forest owners who reject ash recycling motivate this by saying that the forest residues should be left to decompose in the forest, that modern forestry depletes the soils, that payment for the forest fuels is insufficient, and that the spreading of the ash may result in damage on remaining trees and soil. Forest owners who accept recycling appreciate that the ash increases the pH, refer to a recycling perspective, consider that mechanical damage is very limited, and state that they have faith in the extension agent who proposed the activity. Legislation presently permits a simple administration of ash recycling under the auspices of local forestry boards. This lucidity in the legislation and the outspoken desire for this utilisation of wood ash at government level is a singular feat which does not apply to other uses. Two major impediments remain to a large scale recycling of ash to the forest. A general lack of knowledge on all levels and the alternative – usually much lower – cost for other utilisations such as road building, covering of old deposits and others. To be able to make any definite prognoses about the future for ash recycling to the forest a continued investigation of the pricing, sustainability and legal status of these other ways of utilising the ash must be carried out.

Keyword

ash recycling

nutrient

Publication and Content Type

vet (subject category)

rap (subject category)