Carl-Fredrik Johannesson

"Decadal decline in forest floor soil organic carbon after clear-cutting in Nordic and Canadian forests" tinyurl.com/mvefm3wk Paper published! 28-35 years until minimum soil C stock is reached More initial soil C --> more loss Now follow me on BlueSky: bsky.app/profile/cjohan…

Lagom till våren har jag, tillsammans med Felicia Ransmark, släppt en barnbok med skogstema. Utgiven av @rabensjogren som vi haft förmånen att samarbeta med! In och ta er en titt, och vem vet, kanske vill ni köpa den?! tinyurl.com/56p8epsz

If it wasn't for doing a PostDoc @NINAnature , I would be sure to apply for this one about forest soil C cycling: tinyurl.com/4jcjwtc3

@MauriceSundy @klausslar @JenniNorden Thank you! :)

@CFJohannesson @klausslar @JenniNorden Congrats Carl!

This is how happy you are when you've successfully defended your Ph.D. thesis! Lots of people to thank of course, not least my supervisors @klausslar @JenniNorden and Hanna Silvennoinen. This would not have been possible without you! Now onwards!

Avverkningsanmäld areal ökade med 42 % i december 2024 jämfört med 2023. I fjällnära skogar var arealen drygt åtta gånger större än samma månad förra året. #statistik Läs mer: skogsstyrelsen.se/nyhetslista/ok…

@MauriceSundy Congratulations Sandy!! So cool! :)

@Paris_Fungarium, I will have the opportunity to discover the treasures of the fungal collection with the fungal taxonomist Bart Buyck & Isabelle Bouchard-Dufay. We started with an inventory of the 4532 fungal specimens from Madagascar (1996-2022).

After a transitional period between 🇳🇴 and 🇫🇷, I am thrilled to announce that I have joined @ISYEB_UMR as an Associate Professor. I will be a fungal curator at the Museum national d’histoire naturelle in Paris @Paris_Fungarium.

@klausslar @LICOR_ENV Love the coffee/tea in the snow pit!

Master's student Anna Rosendahl and myself visited drained and rewetted mires near Trysil to measure #CO2 #CH4 #N2O in the snow with @LICOR_ENV #LI7810 and #LI7820. Measured up to 16000 ppb CH4. Great data for her thesis :-)

@MauriceSundy @LICOR_ENV @klausslar @JenniNorden @HolgerLange3 Thank you Sandy! One day before submission of PhD thesis, very good timing!

@CFJohannesson @LICOR_ENV @klausslar @JenniNorden @HolgerLange3 Congrats @CFJohannesson et al!

GHG flux rate estimates substantially impacted by chamber closure period length, both linear and Hutchinson-Mosier based! Fresh paper: t.ly/n0s4w Effect largest in high flux regions. Implications for all systems, but this analysis is based on set-up from @LICOR_ENV.

@annvirkk Yupp! Thanks!

@annvirkk I get "Page not found" when clicking the link. Interested in reading! :)

By the way, I'm not disgusted by the person I'm talking to, I'm just not photogenique!

Do you measure GHGs with non-steady-state chambers? How long do you keep your chamber closed? How long you keep it closed can substantially impact your flux estimates! Here presenting my work at #EGU2024. Keep an eye out on my twitter for a coming publication on the subject!

@mdancho84 On the other hand, you could go Bayesian to avoid a black and white world (unless you think the world is functioning as black and white of course).

Understanding P-Values is essential for improving regression models. In 2 minutes, learn what took me 2 years to figure out. 1. The p-value: A p-value, in statistics, is a measure used to assess the strength of the evidence against a null hypothesis. 2. Null Hypothesis (H0): This is a general statement or default position that there is no relationship between two measured phenomena or no association among groups. For example, the regressor does not affect the outcome. 3. Alternative Hypothesis (H1): This is what you want to test for. It is often the opposite of the null hypothesis. For example, that the regressor does affect the outcome. 4. Calculating the p-value: The p-value for each coefficient is typically calculated using the t-test. There are several steps involved. Let's break them down. 5. Coefficient Estimate: In a regression model, you have estimates of coefficients (β) for each predictor. These coefficients represent the change in the dependent variable for a one-unit change in the predictor, holding all other predictors constant. 6. Standard Error of the Coefficient: The standard error (SE) measures the accuracy with which a sample represents a population. In regression, the SE of a coefficient estimate indicates how much variability there is in the estimate of the coefficient. 7. Test Statistic (T): The test statistic for each coefficient in a regression model is calculated by dividing the Coefficient Estimate / Standard Error of the Coefficient. This gives you a t-value. 8. Degrees of Freedom: The degrees of freedom (df) for this test are usually calculated as the number of observations minus the number of parameters being estimated (including the intercept). 9. P-Value Calculation: The p-value is then determined by comparing the calculated t-value to the t-distribution with the appropriate degrees of freedom. The area under the t-distribution curve, beyond the calculated t-value, gives the p-value. 10. Interpretation: A small p-value (usually ≤ 0.05) indicates that it is unlikely to observe such a data pattern if the null hypothesis were true, suggesting that the predictor is a significant contributor to the model. === Ready to learn Data Science for Business? I put together a free on-demand workshop that covers the 10 skills that helped me make the transition to Data Scientist: learn.business-science.io/free-rtrack-ma… And if you'd like to speed it up, I have a live workshop next week where I'll share how to use ChatGPT for Data Science: learn.business-science.io/registration-c… If you like this post, please reshare ♻️ it so others can get value.

@IvikaOstonen @JenniNorden "Only" approx. 2k observations post clear-cutting in forest floors and top mineral soil, approx. 1k in deeper mineral soil! But there's many more observations in total in the dataset (i.e. when including non-clear cuts)!

Loss of carbon stocks after clear-cutting takes decades to recover...coming soon, work based on monitoring data (>60k measurements) from Nordic Forests @CFJohannesson @norforsoil @JenniNorden

Fellow GHG fluxes enthusiasts, I need your help 🙏 I just created a new R package, and I could really use some feedback! Please try it out 👇 github.com/Qepanna/GoFlux… Calculate GHG fluxes in R, from instruments such as LI-7810 from @LICOR_ENV and UGGA from @ABBgroupnews

Ulf Kristersson lovprisade Sveriges natur och de som gör den tillgänglig på instagram. Samtidigt genomför han en historiskt stor nedskärning på just skydd och skötsel av natur. klimatgranskaren.se/vadjan-till-ul…