CI v3 - Don't get any logs

Hi, I've started working on a project on CI v3 and I have noticed that I don't get any log errors, messages warnings at all, the application/logs folder is always empty, which is a little bit weird.

These are my settings:

folder structure:

Code:

- application
-- config
--- development
---- database.php
---- config.php
--- production
---- database.php
---- config.php

And the settings in my config.php files are these:

PHP Code:

// in application/config/development folder
$config['log_threshold'] = 4;

// in application/config/production folder
$config['log_threshold'] = 1; 


I was using the same folder structure and on CI v2 and worked great, I was getting warnings and errors when images where missing
or errors from log_message() etc, however in this doesn't seem to work.

Any ideas how I could fix this?