• *The third step: Building up the full model.*

In this case, the final step consisted of building a full model to account for the direct effect of the lower-lever predictor variables and higher-level predictor ones, including the effect of the interaction terms and random intercept effect. The final model was described as follow:

$$\begin{array}{l} \Pr(\text{Will} = \text{Yes} | \text{x} ) = \gamma 0 + \gamma 1\\ \text{Pr}(\text{Will} = \text{yes} | \text{x} ) = \gamma 2 \text{ Orr} \text{v} + \gamma 2 \text{ Orr} \text{ign} + \gamma 3 \text{Earnili} \text{arity} + \gamma 4 \text{Cons} + \gamma \text{5} \text{Will} \\_q + \gamma \text{6Curions} \text{ity} + \gamma \text{8Age} + \gamma \text{8Age} + \gamma \text{40} + \text{ri} \text{j}. \end{array} \tag{3}$$

In order to understand if the full model was more suitable than the intermediate one, the ANOVA test was applied. In particular, the ANOVA test (Table 4) between the intermediate model Equation (2) and the full model Equation (3) showed that the willingness to consume domestic eucalyptus firewood is significantly influenced by all variables including the supply method (*Forn*) (i.e., loose firewood, firewood arranged in pallets, or firewood in 10–15 kg bags). It can be seen that the AIC values of the full model is smaller than the intermediate model one. This means that adding the supply method (*Forn*) in the model improves the quality of the regression.

**Table 4.** Likelihood ratio test between the intermediate model Equation (2) and the full model Equation (3).


Source: Our elaboration.

Finally, the odds' ratio was calculated to show the probability increase/decrease of the willingness to consume domestic eucalyptus firewood when the considered variable increases or decreases.

The analysis was performed using R version 3.6.2 [39].

#### **3. Results and Discussion**

#### *3.1. Descriptive Statistics*

Within the sample of 282 individuals, 62% were males, average age resulted in about 43 years, 59% of respondents presented a low education level (i.e., primary or secondary school), and 57% of the sample lives in small towns.

Table 5 shows the variables used in the full model, their average values, and standard deviation while Table 6 shows the Pearson correlations among explanatory variables indicating low correlations index among variables used in the full model.





\* *p*-value < 0.05; \*\* *p*-value < 0.01.

In the first parameter of Table 5 (*Will*), 64% of the sample was willing to consume domestic eucalyptus firewood and the theoretical average annual consumption was about 1.5 Mg·yr−1. This finding may indicate that people are becoming more receptive towards eucalyptus, considering it as a suitable firewood alternative.

Moreover, generally, the sample showed attention both to provenience and to the origin of fuelwood and preferred loose firewood as the supply method.

On average, the sample could be willing to consume domestic eucalyptus firewood for its energetic characteristics, even if the respondents did not show curiosity about it. In addition, as a general trend, the sample had neither familiarity (*Familiarity*) or consumed eucalyptus firewood in the past (*Pass*).

*3.2. The Full Multilevel Logistic Regression Model*

The result of the full multilevel logistic regression model is given in Table 7.


**Table 7.** Parametric estimation results for the full model Equation (3).

(Bayesian information criterion) are the well-known model fit indices.

Source: Authors' elaboration.

The parameters *Familiarity*, *Cons*, *Energetic*, and *Forn* resulted to be the most significant in the full model, followed by *Prov*, *Curiosity*, and *Age*. All variables showed a positive sign except *Age*.

Unfortunately, there are not many studies focused on the willingness to consume domestic eucalyptus firewood which could help us to evaluate the findings of the present work, which represent a novelty in this field.

Our findings show that consumers who pay attention to the supply method (*Forn*), i.e., loose firewood, firewood arranged in pallets, or firewood in 10–15 kg bags, are 2.2 times more likely to consume domestic eucalyptus firewood than other consumers.

The knowledge of the existence of eucalyptus (*Familiarity*) as a firewood alternative resulted in an important factor in the consumers' willingness, indeed, those who reported to know it, asserted to be more willing to consume it in the future. In particular, consumers that showed familiarity with eucalyptus firewood are 5.9 times more likely to consume it than other people. Our findings are in line with current literature [40] where familiarity is a key attribute that influences consumer behaviour and, consequently, decision making [41]. In fact, familiarity showed a significant influence on the acceptability of a given product [42]. Moreover, increasing familiarity, through further information, about new products could improve their accepting rate [43] and this aspect resulted to be a key concerning firewood [44]. Johnson et al., (1984) suggested that familiarity involves a process of looking for information and processing both new and already existing goods [45]. In addition, Fischer et al., (2008) showed that the more information the consumers gather, the more products they are willing to purchase [46]. This is an important aspect, taking into consideration that firewood consumption is linked with information received [23], and in general the familiarity with a given product, through available information, could increase the likelihood of consuming it in the future [47].

More recently, Seo et al., (2013) highlighted that familiarity with a product is linked to both level of information [41] and, in accordance with Ryynänen et al., (2018), to previous experience [41,48]. Our findings confirmed this assertion, considering that previous experience with eucalyptus firewood showed an important role in the consumers' willingness. Indeed, respondents who reported previous experiences with eucalyptus firewood (*Cons*) were more willing to consume it again. In particular, people who had previous experiences with eucalyptus firewood are 5.5 times more likely to consume it than other people. Our results are in line with literature about consumer behaviour, where previous experience with an innovative product enhances consumer acceptance [49] and people with previous experiences resulted in having a higher probability to willingly consume it again in future [25].

In our case, the geographic provenience of firewood (*Prov*) (i.e., if firewood comes from tropical countries or Mediterranean ones) also seemed to be one of the reasons that could push people to consume eucalyptus firewood. Indeed, respondents who pay attention to the geographic provenience of firewood are 3.03 times more likely to consume it than other consumers. These findings are also in line with previous literature [50] where the provenience of wood was a key factor that influenced the consumer behaviour. Moreover, according to Paletto et al., (2017) the geographic provenience of wood is one of the most relevant factors in the enhancement strategies for local fuelwood [29]. The consumer relies on the image of place of production (negative or positive) as a quality standard [24]. In this framework, attention towards geographic provenience of firewood could imply benefits for Italian local economies [29], especially in Southern Italy where eucalyptus is usually located [2].

Moreover, curiosity towards a new product also demonstrated a certain importance in the respondents' choice. In particular, those who showed a positive attitude about new products (*Curiosity*) resulted to be 1.3 times more willing to consume domestic eucalyptus firewood. Similar results were reported by Palmieri et al., (2020), which showed that willingness to consume a new product is linked to consumers' curiosity towards new products [25].

It is well known that the combustion of wood in fireplaces involves a very low level of technology, with an equally low energy conversion efficiency. For this reason, it is not surprising that the consumer described by the sample showed a marked interest in technical aspects related to the quality of the wood to be burned. In fact, energetic density of firewood (*Energetic*) was another factor that had an important influence on respondents' choice. Technical aspects such as energetic density could shape the respondents' behaviour. In particular, people who pay attention to the energetic aspect of firewood are 2.1 times more likely to consume it than other people. Vásquez Lavin et al., (2020) also reported that technical aspects such as heating value and moisture of firewood were considered very important for what concern consumer's choice [51]. Similar results were confirmed by other studies [23] where energetic density of firewood played an important role in consumer choices. This aspect could be very interesting, taking into account that eucalyptus firewood has similar heating value to other fuelwood species, for example oak [22].

Another significant variable in our model was the consumer's age. Indeed, respondents' age resulted to be an important driver and was negatively associated with willingness to consume domestic eucalyptus firewood. According to our results, younger people showed a higher willingness to consume eucalyptus firewood than older ones. In fact, young people are 0.1 times more likely to consume it than older people. Similar results were found by some authors [25], where age exerted a negative effect on the probability to willingly consume a given new product. On the other hand, this aspect cannot be generalized because other authors reported that respondents' age had no significant influence on preference [50].

#### **4. Conclusions**

Italy is one of the world's major importers of firewood and medium rotation eucalyptus plantations could represent a source of biomass for the firewood market. Although, excluding some areas of Southern Italy, the eucalyptus is a wood species not extensively used as firewood. People's willingness to consume a product depend on several parameters including the different supply methods of a product.

This study aimed to understand consumer willingness to consume domestic eucalyptus firewood and their motivations by considering the preferred supply method.

Although the sample of this research cannot be considered representative of the entire Italian population, as happens in many studies about consumer behaviour, the results obtained gave interesting hints to understand the process of consumer decision-making. In fact, further studies are necessary to better understand the Italian consumers' propensity towards eucalyptus fuelwood acceptance, in terms of their individual preferences, attitudes, or concerns.

This research suggested that factors such as age, previous experience, familiarity, supply method, attitude towards new product, provenience, and technical characteristics of firewood, i.e., energetic density, play an important role in shaping individual behaviour concerning eucalyptus firewood consumption. In summary, the owners of eucalyptus plantations should address themselves towards informed young people, curious, who already know eucalyptus as fuelwood species, and who pay attention to the supply method, provenience, and technical characteristics of firewood (i.e., heating value). Our results are interesting, taking into consideration that eucalyptus plantations are less environmentally impactful than other crops, therefore developing a eucalyptus fuelwood value chain could reduce the environmental impacts linked to firewood production.

Even if the conclusions of the present work cannot be over-generalised, the present findings could open new spaces for domestic eucalyptus firewood, considering that the quantity and quality of information could shape the probability that people would be willing to consume it. In conclusion, a growing eucalyptus demand as sustainable firewood alternative would be an interesting opportunity for farmers to enter the sector and target themselves to specific market niches.

**Author Contributions:** N.P. contributed to the study design, data collection, data analysis, writing, and revising of the whole manuscript. A.S. and F.L. contributed to the study design and revising of the whole manuscript. L.P. contributed to the study supervision, project administration, and funding acquisition. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 744821 and the APC was funded by Becool Project. This research was partly carried out within both the Becool Project funded by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 744821; and the AGROENER project (D.D. n. 26329, 1 April 2016) funded by the Italian Ministry of Agriculture (MiPAAF). The ideas expressed do not represent either those of the European Commission or the Italian Ministry of Agriculture (MiPAAF).

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


51. Vásquez Lavin, F.; Barrientos, M.; Castillo, Á.; Herrera, I.; Ponce Oliva, R.D. Firewood certification programs: Key attributes and policy implications. *Energy Policy* **2020**, *137*, 111160. [CrossRef]

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